diff --git a/lib/shared/thread-utils.js b/lib/shared/thread-utils.js
--- a/lib/shared/thread-utils.js
+++ b/lib/shared/thread-utils.js
@@ -60,8 +60,10 @@
 import type {
   MinimallyEncodedMemberInfo,
   MinimallyEncodedRawThreadInfo,
+  MinimallyEncodedRelativeMemberInfo,
   MinimallyEncodedRoleInfo,
   MinimallyEncodedThreadCurrentUserInfo,
+  MinimallyEncodedThreadInfo,
 } from '../types/minimally-encoded-thread-permissions-types.js';
 import { userRelationshipStatus } from '../types/relationship-types.js';
 import {
@@ -119,7 +121,12 @@
 import { pendingThreadIDRegex } from '../utils/validation-utils.js';
 
 function threadHasPermission(
-  threadInfo: ?(ThreadInfo | RawThreadInfo | MinimallyEncodedRawThreadInfo),
+  threadInfo: ?(
+    | ThreadInfo
+    | RawThreadInfo
+    | MinimallyEncodedRawThreadInfo
+    | MinimallyEncodedThreadInfo
+  ),
   permission: ThreadPermission,
 ): boolean {
   if (!threadInfo) {
@@ -137,7 +144,12 @@
 }
 
 function viewerIsMember(
-  threadInfo: ?(ThreadInfo | RawThreadInfo | MinimallyEncodedRawThreadInfo),
+  threadInfo: ?(
+    | ThreadInfo
+    | RawThreadInfo
+    | MinimallyEncodedRawThreadInfo
+    | MinimallyEncodedThreadInfo
+  ),
 ): boolean {
   return !!(
     threadInfo &&
@@ -147,14 +159,24 @@
 }
 
 function threadIsInHome(
-  threadInfo: ?(ThreadInfo | RawThreadInfo | MinimallyEncodedRawThreadInfo),
+  threadInfo: ?(
+    | ThreadInfo
+    | RawThreadInfo
+    | MinimallyEncodedRawThreadInfo
+    | MinimallyEncodedThreadInfo
+  ),
 ): boolean {
   return !!(threadInfo && threadInfo.currentUser.subscription.home);
 }
 
 // Can have messages
 function threadInChatList(
-  threadInfo: ?(ThreadInfo | RawThreadInfo | MinimallyEncodedRawThreadInfo),
+  threadInfo: ?(
+    | ThreadInfo
+    | RawThreadInfo
+    | MinimallyEncodedRawThreadInfo
+    | MinimallyEncodedThreadInfo
+  ),
 ): boolean {
   return (
     viewerIsMember(threadInfo) &&
@@ -163,31 +185,56 @@
 }
 
 function threadIsTopLevel(
-  threadInfo: ?(ThreadInfo | RawThreadInfo | MinimallyEncodedRawThreadInfo),
+  threadInfo: ?(
+    | ThreadInfo
+    | RawThreadInfo
+    | MinimallyEncodedRawThreadInfo
+    | MinimallyEncodedThreadInfo
+  ),
 ): boolean {
   return threadInChatList(threadInfo) && threadIsChannel(threadInfo);
 }
 
 function threadIsChannel(
-  threadInfo: ?(ThreadInfo | RawThreadInfo | MinimallyEncodedRawThreadInfo),
+  threadInfo: ?(
+    | ThreadInfo
+    | RawThreadInfo
+    | MinimallyEncodedRawThreadInfo
+    | MinimallyEncodedThreadInfo
+  ),
 ): boolean {
   return !!(threadInfo && threadInfo.type !== threadTypes.SIDEBAR);
 }
 
 function threadIsSidebar(
-  threadInfo: ?(ThreadInfo | RawThreadInfo | MinimallyEncodedRawThreadInfo),
+  threadInfo: ?(
+    | ThreadInfo
+    | RawThreadInfo
+    | MinimallyEncodedRawThreadInfo
+    | MinimallyEncodedThreadInfo
+  ),
 ): boolean {
   return threadInfo?.type === threadTypes.SIDEBAR;
 }
 
 function threadInBackgroundChatList(
-  threadInfo: ?(ThreadInfo | RawThreadInfo | MinimallyEncodedRawThreadInfo),
+  threadInfo: ?(
+    | ThreadInfo
+    | RawThreadInfo
+    | MinimallyEncodedRawThreadInfo
+    | MinimallyEncodedThreadInfo
+  ),
 ): boolean {
   return threadInChatList(threadInfo) && !threadIsInHome(threadInfo);
 }
 
 function threadInHomeChatList(
-  threadInfo: ?(ThreadInfo | RawThreadInfo | MinimallyEncodedRawThreadInfo),
+  threadInfo: ?(
+    | ThreadInfo
+    | RawThreadInfo
+    | MinimallyEncodedRawThreadInfo
+    | MinimallyEncodedThreadInfo
+  ),
 ): boolean {
   return threadInChatList(threadInfo) && threadIsInHome(threadInfo);
 }
@@ -195,7 +242,12 @@
 // Can have Calendar entries,
 // does appear as a top-level entity in the thread list
 function threadInFilterList(
-  threadInfo: ?(ThreadInfo | RawThreadInfo | MinimallyEncodedRawThreadInfo),
+  threadInfo: ?(
+    | ThreadInfo
+    | RawThreadInfo
+    | MinimallyEncodedRawThreadInfo
+    | MinimallyEncodedThreadInfo
+  ),
 ): boolean {
   return (
     threadInChatList(threadInfo) &&
@@ -205,7 +257,12 @@
 }
 
 function userIsMember(
-  threadInfo: ?(ThreadInfo | RawThreadInfo | MinimallyEncodedRawThreadInfo),
+  threadInfo: ?(
+    | ThreadInfo
+    | RawThreadInfo
+    | MinimallyEncodedRawThreadInfo
+    | MinimallyEncodedThreadInfo
+  ),
   userID: string,
 ): boolean {
   if (!threadInfo) {
@@ -219,7 +276,10 @@
 
 function threadActualMembers(
   memberInfos: $ReadOnlyArray<
-    MemberInfo | RelativeMemberInfo | MinimallyEncodedMemberInfo,
+    | MemberInfo
+    | RelativeMemberInfo
+    | MinimallyEncodedMemberInfo
+    | MinimallyEncodedRelativeMemberInfo,
   >,
 ): $ReadOnlyArray<string> {
   return memberInfos
@@ -228,7 +288,11 @@
 }
 
 function threadOtherMembers<
-  T: MemberInfo | RelativeMemberInfo | MinimallyEncodedMemberInfo,
+  T:
+    | MemberInfo
+    | RelativeMemberInfo
+    | MinimallyEncodedMemberInfo
+    | MinimallyEncodedRelativeMemberInfo,
 >(memberInfos: $ReadOnlyArray<T>, viewerID: ?string): $ReadOnlyArray<T> {
   return memberInfos.filter(
     memberInfo => memberInfo.role && memberInfo.id !== viewerID,
@@ -236,7 +300,11 @@
 }
 
 function threadMembersWithoutAddedAshoat<
-  T: ThreadInfo | RawThreadInfo | MinimallyEncodedRawThreadInfo,
+  T:
+    | ThreadInfo
+    | RawThreadInfo
+    | MinimallyEncodedRawThreadInfo
+    | MinimallyEncodedThreadInfo,
 >(threadInfo: T): $PropertyType<T, 'members'> {
   if (threadInfo.community !== genesis.id) {
     return threadInfo.members;
@@ -246,12 +314,18 @@
   );
 }
 
-function threadIsGroupChat(threadInfo: ThreadInfo): boolean {
+function threadIsGroupChat(
+  threadInfo: ThreadInfo | MinimallyEncodedThreadInfo,
+): boolean {
   return threadInfo.members.length > 2;
 }
 
 function threadOrParentThreadIsGroupChat(
-  threadInfo: RawThreadInfo | ThreadInfo | MinimallyEncodedRawThreadInfo,
+  threadInfo:
+    | RawThreadInfo
+    | ThreadInfo
+    | MinimallyEncodedRawThreadInfo
+    | MinimallyEncodedThreadInfo,
 ) {
   return threadMembersWithoutAddedAshoat(threadInfo).length > 2;
 }
@@ -265,7 +339,11 @@
 }
 
 function getSingleOtherUser(
-  threadInfo: ThreadInfo | RawThreadInfo | MinimallyEncodedRawThreadInfo,
+  threadInfo:
+    | ThreadInfo
+    | RawThreadInfo
+    | MinimallyEncodedRawThreadInfo
+    | MinimallyEncodedThreadInfo,
   viewerID: ?string,
 ): ?string {
   if (!viewerID) {
@@ -456,7 +534,9 @@
 
 // Returns map from lowercase username to AccountUserInfo
 function memberLowercaseUsernameMap(
-  members: $ReadOnlyArray<RelativeMemberInfo>,
+  members: $ReadOnlyArray<
+    RelativeMemberInfo | MinimallyEncodedRelativeMemberInfo,
+  >,
 ): Map<string, AccountUserInfo> {
   const memberMap = new Map();
   for (const member of members) {
@@ -472,7 +552,7 @@
 // Returns map from user ID to AccountUserInfo
 function extractMentionedMembers(
   text: string,
-  threadInfo: ThreadInfo,
+  threadInfo: ThreadInfo | MinimallyEncodedThreadInfo,
 ): Map<string, AccountUserInfo> {
   const memberMap = memberLowercaseUsernameMap(threadInfo.members);
   const mentions = extractUserMentionsFromText(text);
@@ -491,8 +571,8 @@
 // they will be automatically added to that sidebar
 function extractNewMentionedParentMembers(
   messageText: string,
-  threadInfo: ThreadInfo,
-  parentThreadInfo: ThreadInfo,
+  threadInfo: ThreadInfo | MinimallyEncodedThreadInfo,
+  parentThreadInfo: ThreadInfo | MinimallyEncodedThreadInfo,
 ): AccountUserInfo[] {
   const mentionedMembersOfParent = extractMentionedMembers(
     messageText,
@@ -946,7 +1026,7 @@
 }
 
 function getMinimallyEncodedCurrentUser(
-  threadInfo: MinimallyEncodedRawThreadInfo,
+  threadInfo: MinimallyEncodedRawThreadInfo | MinimallyEncodedThreadInfo,
   viewerID: ?string,
   userInfos: UserInfos,
 ): MinimallyEncodedThreadCurrentUserInfo {
@@ -968,7 +1048,11 @@
 }
 
 function threadIsWithBlockedUserOnly(
-  threadInfo: RawThreadInfo | ThreadInfo | MinimallyEncodedRawThreadInfo,
+  threadInfo:
+    | RawThreadInfo
+    | ThreadInfo
+    | MinimallyEncodedRawThreadInfo
+    | MinimallyEncodedThreadInfo,
   viewerID: ?string,
   userInfos: UserInfos,
   checkOnlyViewerBlock?: boolean,
@@ -1000,7 +1084,11 @@
 }
 
 function threadFrozenDueToBlock(
-  threadInfo: RawThreadInfo | ThreadInfo | MinimallyEncodedRawThreadInfo,
+  threadInfo:
+    | RawThreadInfo
+    | ThreadInfo
+    | MinimallyEncodedRawThreadInfo
+    | MinimallyEncodedThreadInfo,
   viewerID: ?string,
   userInfos: UserInfos,
 ): boolean {
@@ -1008,7 +1096,11 @@
 }
 
 function threadFrozenDueToViewerBlock(
-  threadInfo: RawThreadInfo | ThreadInfo | MinimallyEncodedRawThreadInfo,
+  threadInfo:
+    | RawThreadInfo
+    | ThreadInfo
+    | MinimallyEncodedRawThreadInfo
+    | MinimallyEncodedThreadInfo,
   viewerID: ?string,
   userInfos: UserInfos,
 ): boolean {
@@ -1023,8 +1115,16 @@
 };
 
 function memberIsAdmin(
-  memberInfo: RelativeMemberInfo | MemberInfo | MinimallyEncodedMemberInfo,
-  threadInfo: ThreadInfo | RawThreadInfo | MinimallyEncodedRawThreadInfo,
+  memberInfo:
+    | RelativeMemberInfo
+    | MemberInfo
+    | MinimallyEncodedMemberInfo
+    | MinimallyEncodedRelativeMemberInfo,
+  threadInfo:
+    | ThreadInfo
+    | RawThreadInfo
+    | MinimallyEncodedRawThreadInfo
+    | MinimallyEncodedThreadInfo,
 ): boolean {
   return !!(
     memberInfo.role && roleIsAdminRole(threadInfo.roles[memberInfo.role])
@@ -1038,7 +1138,8 @@
     | RelativeMemberInfo
     | MemberInfo
     | ServerMemberInfo
-    | MinimallyEncodedMemberInfo,
+    | MinimallyEncodedMemberInfo
+    | MinimallyEncodedRelativeMemberInfo,
 ): boolean {
   if (memberInfo.minimallyEncoded) {
     return hasPermission(memberInfo.permissions, threadPermissions.CHANGE_ROLE);
@@ -1058,6 +1159,7 @@
     | ThreadInfo
     | ServerThreadInfo
     | MinimallyEncodedRawThreadInfo
+    | MinimallyEncodedThreadInfo
   ),
 ): boolean {
   if (!threadInfo) {
@@ -1067,7 +1169,11 @@
 }
 
 function threadOrParentThreadHasAdminRole(
-  threadInfo: RawThreadInfo | ThreadInfo | MinimallyEncodedRawThreadInfo,
+  threadInfo:
+    | RawThreadInfo
+    | ThreadInfo
+    | MinimallyEncodedRawThreadInfo
+    | MinimallyEncodedThreadInfo,
 ) {
   return (
     threadMembersWithoutAddedAshoat(threadInfo).filter(member =>
@@ -1306,7 +1412,8 @@
     | ServerThreadInfo
     | RawThreadInfo
     | ThreadInfo
-    | MinimallyEncodedRawThreadInfo,
+    | MinimallyEncodedRawThreadInfo
+    | MinimallyEncodedThreadInfo,
   memberID: string,
   permission: ThreadPermission,
 ): boolean {
@@ -1323,7 +1430,7 @@
 }
 
 function useCanCreateSidebarFromMessage(
-  threadInfo: ThreadInfo,
+  threadInfo: ThreadInfo | MinimallyEncodedThreadInfo,
   messageInfo: ComposableMessageInfo | RobotextMessageInfo,
 ): boolean {
   const messageCreatorUserInfo = useSelector(
@@ -1352,7 +1459,7 @@
 }
 
 function useSidebarExistsOrCanBeCreated(
-  threadInfo: ThreadInfo,
+  threadInfo: ThreadInfo | MinimallyEncodedThreadInfo,
   messageItem: ChatMessageInfoItem,
 ): boolean {
   const canCreateSidebarFromMessage = useCanCreateSidebarFromMessage(
@@ -1385,7 +1492,8 @@
     | ?ServerThreadInfo
     | RawThreadInfo
     | ThreadInfo
-    | MinimallyEncodedRawThreadInfo,
+    | MinimallyEncodedRawThreadInfo
+    | MinimallyEncodedThreadInfo,
   threadType: ThreadType,
 ): ?string {
   if (!parentThreadInfo) {
@@ -1405,7 +1513,8 @@
     | ?ServerThreadInfo
     | RawThreadInfo
     | ThreadInfo
-    | MinimallyEncodedRawThreadInfo,
+    | MinimallyEncodedRawThreadInfo
+    | MinimallyEncodedThreadInfo,
 ): ?string {
   if (!parentThreadInfo) {
     return null;
@@ -1504,7 +1613,7 @@
 }
 
 function removeMemberFromThread(
-  threadInfo: ThreadInfo,
+  threadInfo: ThreadInfo | MinimallyEncodedThreadInfo,
   memberInfo: RelativeMemberInfo,
   dispatchActionPromise: DispatchActionPromise,
   removeUserFromThreadServerCall: (
@@ -1523,7 +1632,7 @@
 }
 
 function switchMemberAdminRoleInThread(
-  threadInfo: ThreadInfo,
+  threadInfo: ThreadInfo | MinimallyEncodedThreadInfo,
   memberInfo: RelativeMemberInfo,
   isCurrentlyAdmin: boolean,
   dispatchActionPromise: DispatchActionPromise,
@@ -1555,8 +1664,8 @@
 }
 
 function getAvailableThreadMemberActions(
-  memberInfo: RelativeMemberInfo,
-  threadInfo: ThreadInfo,
+  memberInfo: RelativeMemberInfo | MinimallyEncodedRelativeMemberInfo,
+  threadInfo: ThreadInfo | MinimallyEncodedThreadInfo,
   canEdit: ?boolean = true,
 ): $ReadOnlyArray<'change_role' | 'remove_user'> {
   const role = memberInfo.role;
@@ -1620,7 +1729,11 @@
 }
 
 function threadInfoInsideCommunity(
-  threadInfo: RawThreadInfo | ThreadInfo | MinimallyEncodedRawThreadInfo,
+  threadInfo:
+    | RawThreadInfo
+    | ThreadInfo
+    | MinimallyEncodedRawThreadInfo
+    | MinimallyEncodedThreadInfo,
   communityID: string,
 ): boolean {
   return threadInfo.community === communityID || threadInfo.id === communityID;
@@ -1631,7 +1744,7 @@
 };
 
 function useRoleMemberCountsForCommunity(
-  threadInfo: ThreadInfo,
+  threadInfo: ThreadInfo | MinimallyEncodedThreadInfo,
 ): RoleAndMemberCount {
   return React.useMemo(() => {
     const roleIDsToNames = {};
@@ -1697,7 +1810,11 @@
 }
 
 function communityOrThreadNoun(
-  threadInfo: RawThreadInfo | ThreadInfo | MinimallyEncodedRawThreadInfo,
+  threadInfo:
+    | RawThreadInfo
+    | ThreadInfo
+    | MinimallyEncodedRawThreadInfo
+    | MinimallyEncodedThreadInfo,
 ): string {
   return threadTypeIsCommunityRoot(threadInfo.type)
     ? 'community'
@@ -1705,7 +1822,11 @@
 }
 
 function getThreadsToDeleteText(
-  threadInfo: RawThreadInfo | ThreadInfo | MinimallyEncodedRawThreadInfo,
+  threadInfo:
+    | RawThreadInfo
+    | ThreadInfo
+    | MinimallyEncodedRawThreadInfo
+    | MinimallyEncodedThreadInfo,
 ): string {
   return `${
     threadTypeIsCommunityRoot(threadInfo.type)
diff --git a/lib/types/thread-types.js b/lib/types/thread-types.js
--- a/lib/types/thread-types.js
+++ b/lib/types/thread-types.js
@@ -48,11 +48,11 @@
   isSender: t.Boolean,
 });
 
-export type RelativeMemberInfo = {
+export type RelativeMemberInfo = $ReadOnly<{
   ...MemberInfo,
   +username: ?string,
   +isViewer: boolean,
-};
+}>;
 const relativeMemberInfoValidator = tShape<RelativeMemberInfo>({
   ...memberInfoValidator.meta.props,
   username: t.maybe(t.String),