How to swap models?

[skypalace]

I am trying to swap out Barret's model for Rufus (or at least any other model)

I got Ifalna from here:

https://www.ff7catalog.com/threads/8913/

I found Barret at these files:

SBAA
SCAA
SDAA
SEAA

and Rufus at this file:

CIAA


So what I tried to do was delete the existing SBAA, SCAA, SDAA, SEAA files, and instead copy the CIAA file 4 times, and rename the copies SBAA, SCAA, SDAA, SEAA

I loaded up the game, went into combat with Barret, game crashed.

Was hoping that would magically swap out the models but it didn't work.

What am I missing here where am I going wrong?

Any help appreciated, thanks!