What do you mean by break things? Are you talking about code, or balance? I can totally understand the latter, because I can't picture voring that isn't either too slow to be useful, or too fast to retain spacing.
Can't you just add a flag for modded enemies? Also, what do you mean "some modded enemies are pred-only type characters?" if modded boss enemies are in the mansion, then that probably means they got eaten or killed to begin with. It'd be like making a game where everyone is stuck inside something's stomach, having a switch protagonist, then a modder having a hang up about your protagonist eating them. Like, uh, that ship already sailed a long time ago.