How to structure blend files for game dev

I'm working on a game that has these objects:
Character, Weapons, Mounts.
I'm trying to figure out the right way to structure this project (on the art side only).

The Character has its own animations and animations for different mounts and for different weapons.

I was thinking to put all the mounts in one file, and all the weapons in another file, and create maybe another file to make all the animations of them combined? so a blend file just for animations?

then I need to export it to Unity. I can export every weapon by itself, and every mount with its animations, but then how should I export the character? from the "master" blend file?

also, what if I should sync some animations, like the mount and the character are doing something the requires sync. how can I export an animation like this?

Does anyone know a good article about it or an open-source project that is well structured?

Thanks!