I searched and only found some tangential answers, so:
1. Is there a way to make a creature drop an item both on death and on butchering? Creatures with ITEMCORPSE drop on death, but seem to drop nothing when butchered.
2. And can I change the way butchery works so that I only get the 'extra butcher object'?
e.g.
I have a tree giant with
[EXTRA_BUTCHER_OBJECT:BY_TOKEN:HEART]
[EBO_ITEM:WOOD:NONE:PLANT_MAT:BIRCH:WOOD]
which drops the extra log on butchering (as long as it doesn't have an ITEMCORPSE), but it also drops huge stacks of wood (~400), even though it has NOBONES, NOMEAT, NOSKIN, NOSKULL. Also, NOT_BUTCHERABLE doesn't seem to do anything at all, but the entity I'm using thinks it's okay to butcher sentients, so that might be interfering.
Any suggestions/advice welcome
1. I believe the only way to obtain items from a creature
on death is with ITEMCORPSE, which as you say, precludes the ability to butcher any remains.
There may be way to do what you want using a syndrome hoop, but I'm not well versed enough to put that together. Maybe one of the other more experienced syndrome modders can think of a way to have a dead creature resurrect, split, transform, and die again, leaving you two different corpses (if that is possible).
2. Does the material used for the tree giant tissues have the token [BUTCHER_SPECIAL:WOOD:NONE]? If, for example, your tree giant uses the WOOD_TEMPLATE in the creature mat for its tissues, and your game has been modded by things like Modest Mod or Accelerated Modest Mod, then the BUTCHER_SPECIAL token will be there. Something to check at least.