As the title says, putting a generator on FloatLizards (both regular and xmas) causes them to always spawn a copter when shot down, regardless of what setting you may choose beforehand.
This seems to be a symptom of the generator event's parameters essentially overwriting whatever settings you made to a given event prior to adding the generator. It's something that seems to affect essentially all events (for example the shootable spike balls completely break once you apply a generator to them).

For most events it's a non-issue as they either have no parameters or they don't exactly despawn to begin with, but flying lizards are a regular enemy someone might actually want to respawn and do so without worrying about copters undermining level design.

This seems to be a symptom of the generator event's parameters essentially overwriting whatever settings you made to a given event prior to adding the generator.

This is a very reasonable guess but it's not actually true in this case--float lizards are coded specifically to always have copters if created in any unusual way. You can verify this by looking in g_Ai.c.

This is definitely the weakness of the Generator system, and probably why most events with lots of parameters seem to be zones, not objects, so they don't have to worry about this. I suspect, though--without actually doing any work to check--that there are a decent handful of existing levels that use respawning float lizards for exactly this purpose, providing a reliable source of copters until the player gets out of that area. I think maybe this pack does that? So I wouldn't want to get rid of the existing behavior, but I do see the argument that it somewhat limits your options, and isn't affected by jjDelayGeneratedCrateOrigins. A hypothetical setting jjGeneratingFloatLizardsSpawnCopters would do the trick but feels a little heavy-handed, idk, maybe it's fine. Someone could also write something up for https://www.jazz2online.com/snippets/ that changed the behavior, since, again, this is actually float-lizard-specific.

Just encountered similar issues with bird morph boxes, which after adding a generator always default to the blue bird in plus.
Maybe in the future there will be a way to modify generated events with parameters. In the meantime I'll try asking around on discord for any script based workarounds.

Bird morphs are already handled by jjDelayGeneratedCrateOrigins, so you can easily have both kinds of bird morphs generating in the same level.

Oh, okay.
I should have been more observant. I was too focused on snippets and mutators to check the actual readme. Sorry for the needlessly reviving the thread.