So, a different take on the question.... if I want to *back out* of some of the changes, I can do it piecemeal, right? Like, if I want to keep the generic fat, and leather, but have individual meats, organs, etc I'd change the [TISSUE_MATERIAL:CREATURE_MAT:ANIMAL:MUSCLE]
to [TISSUE_MATERIAL:LOCAL_CREATURE_MAT:MUSCLE]
, and that's it? The game's not going to freak out because there's a zillion different meats but only one kind of skin?
It can go very "piecemeal" not sure what that completely means as a whole but I'd assume saying using bits of it here and there. Which can be done.
If you have a generic animal like I posted above you can take any element from it as you wish. Easy way for at least generic Tallow and Leather would be to dig into the "material_templates.txt" and change the MATERIAL_REACTION_PRODUCT to something like ANIMAL:TALLOW/LEATHER depending on FAT and SKIN
or if you just wanted generic FATs and SKINs on creatures just each one below BODY_DETAIL_PLAN:STANDARD_MATERIALS and TISSUES use REMOVE_MATERIAL:FAT and SKIN, REMOVE_TISSUE:FAT and SKIN then create two tissue templates that take the ANIMALs FAT and SKIN and add them in your desireed creature after the removed tissues USE_TISSUE_TEMPLATE:FAT:ANIMAL_FAT_TEMPLATE same for skin or any other tissues you wish to replace.
Might take some time if doing each one by hand or create new Body detail plans for materials and tissues like:
GENERIC_ANIMAL_MATERIALS (has no FAT or SKIN)
GENERIC_ANIMAL_TISSUES (the FAT and SKIN use ANIMAL_FAT and SKIN_TEMPLATEs)
and all animals that you want to have generic fat and skin just trade those in from the STANDARD_ body plans
Remember a tissue is what gets butchered and a tissue can have any material it wants, so if you have a tissue that overrides a local material just remove that local material to save on DF memory space (not sure if a material sitting idle and never being used causes any clutter or not.)