I think the wiki needs to be updated for custom spawns to answer the following questions: 1) Can they be renamed with a name tag? 2) If they can, can they still despawn after x days (usually 60)? Side note: if they can be renamed with a name tag, it would be extremely funny to rename them dinnerbone. lol
You see in the Image below I renamed a super turkey DINNERBONE You see the Renamed Super Turkey DINNERBONE was killed and dropped stuff. The Image below shows in red chat that i could not change the name of this entity and thats when i tried to change the eyeenders name with a name tag.
That's interesting. You can rename event bosses, but not the minor bosses. And dinnerbone doesn't turn the mob upside down. Nice to know. (Now, if it was in the wiki...)