A newbie here, and this is my first post. Been playing FF since I can remember.

After reaching level 50 on my party, I realized I cannot get Dualcast, Cry, and I forget what else, because I did not give the 3 augments to the twins early on before they were petrified.

I know you can finish the game without these abilities, but man is it taking forever. I cannot for the life of me destroy the Wall Demon in the Sealed Cave.
Any help would be greatly appreciated. . .
Thank you!!