Updated to Yes - Partially, because don't guarantee deletion of all data.
I don't know what you mean. Mastodon deletes all the data from the server, and sends out delete payloads to other servers that may have stored copies. If you refer to the fact that some of those copies may remain, then you need to mark all services as not allowing account deletion because Google may have caches of indexed profile and post pages.
Changed, replied to another message.
Very true, most other services don't even try to delete all data like messages received by others. Changed.