You would have to update the entire animation set for the battle model to do so.
The other problem will be with character models in particular because they have a special bone (weapon bone) and it's likely to cause a bit of a problem.
Cloud Tiffa Barret Cid Cait Sith Sephiroth Yufi Vincent each have there own weapon models and animations.
Limit breaks are seperate in terms of animations, with vincent it's seperate models. Limit breaks are coded mostly.
Cyb