You really don’t need to bother with enabling physical attacks. Physical attacks do a minimal amount of damage anyway, and you should have something for every character to do besides that (yes, even Zidane needs to be using items, because that’s really the most useful thing he can do when he doesn’t have trance). Now, generally it’s a good idea to have at least one means of doing 9999 damage that’s consistent. For me, that was Frog Drop, and that worked well because Quina always did 9999 with Frog Drop, even when mini. The same thing applies with Freya’s Dragon Crest if you’ve defeated enough dragons, which you can do by casting Quina’s Level 5 Death on Grand Dragons. The other one is Steiner’s Shock, but that one costs much more MP and it becomes weak when he is mini.
What the heck? Ozma in the Chocobo air garden? Wow! I am off to fight him now!