Starting to work on a new set of flags for A_SpawnItemEx, which should let it act similar to how RandomSpawner does, by transferring its own args, special, spawn flags and etc. to the newly spawned actor. Quick test with KDiZD Z1M3 showed promising results, might try to implement some form of boss tracking like it has as well.
Why you ask? Because I can spawn multiple actors in one go with SpawnItemEx with greater flexibility (and ease) than just using RandomSpawner. So hey, good thing it's ToB only!
EDIT: Scratch the idea of tracking bosses, that'd require rewriting the entire function. I'd prefer to leave that handling for RandomSpawner.