From SteveParrot's comment:

I was wondering if it is/could be possible to change the texture of the leaves falling from individual (leaf) blocks. I'm aware resourcepacks can change the leaf particle textures, but they make all non-conifer leaf blocks share the same particle texture. Could this be configurable in some way? Or could the mod include different particles for each leaf block, considering the leaves on the blocks look different from one another? In that case a simple resourcepack could change them with ease.

This may be possible by changing the SpriteProvider depending on the block state:

May require a separate texture atlas from the custom textures (sounds hard) which is then used in a custom SpriteProvider (sounds easy).