Can Leo and Banon be recruited in the World of Ruin?

For the FF6: Return of the Dark Sorcerer Hack, Leo will be playable after the banquet (when you get to Albrook), and all the way through the fire house in Thamasa. As of now, he leaves with shadow in search for the espers. However, it seems it might change now at any time.

I think I might try to introduce a new character instead in the WOR using Leo's or one of the moogle's actor number. It would be a greater challenge but the result would be 10 times better than having a temporary character. If you manage to fix all the glitches it mean there would be room for one more playable character and maybe two if we count Banon, unless he HAS to take someone's place like Umaro. There will be a lot of code to change to make a fully playable, equipable, character that can learn magic.

But how the game mix Banon and Leo in the colosseum surpass my understanding of the code.