I thought kozuka and wakizashi were both types of weapons. The attacks are named after them so it would make sense if the attack diagoro was named after the attack

You can change the name of yuna's dog in ffx-2 anyways, so the name difference is negligible.

However, since diagoro was a part of yojimbo's fayth, it's unlikely he would've made it to x-2. They just reused the character model.

(it's a neat thought though)