Updating Old Hippogrpyhs to Emerald Hippogrpyh Model

[Buttonmasher]

Okay, so let me explain quickly. I'm fairly new to customising files. I recently changed the texture files for the Emerald Hippogryph to essentially be an updated vanilla hippogryph.
I was wondering how I could change all of the models of vanilla hippogryphs excluding the textures?
Right now I have it so that every single one is updated except for that they all are just simply copying the Emerald. I don't want it to take the textures from the Emerald.

How I want it is that I made the Emerald Hippogryph texture and altered it to look like the vanilla colour scheme, but updated textures, etc.
BUT, I want the Vanilla hippogryph to have the Emerald Hippogryph model, because they're slightly different. They share the same skeleton, but the wire is different. The Emerald HIppogryph has more polygons, so the textures blow up. I either get a giant mess, or a vanilla hippogryph with mismatching texture files.

I've tried every combination of .m2 and .skin file enabled, but they don't appear to work. :c
Thanks in advance if anybody knows what I'm talking about and can help me.