Texture Layering for Non-Biped Entities

I'm attempting to make layered textures for some of my mobs, similar to how armor is layered on top of a biped model. For instance, if I have an animal that can have a saddle, chest, and armor equipped, I want these to be visible. I had thought about making a texture with each (1 texture with none, 1 texture with a saddle, 1 texture with a saddle and chest, etc) and switching the applicable texture via procedure when something is equipped, but some of my mobs have too many combinations for this to be feasible. I know textures can be layered in Blockbench, but does this carry over in the java file or texture files into MCreator? Or is there some sort of copy/paste in the entity file I can utilize? I know I can use a procedure to recognize whether or not something is equipped via logic NBT tags, and I could then have a texture change proc off of that logic tag, but I don't know how to tell MCreator to layer a texture on top of the existing base texture rather than just replacing it. Any ideas?

Not looking for "learn to code it yourself" answers. I'll keep fiddling to figure it out just want to know if anyone has any ideas that will save me months of tinkering.