Someone really should try this, and maybe see about altering the stats and maybe the passive abilities they yield.

Kinda defeats the purpose of Eidolon Battles and the Final Boss.

Seventh Ark? What is this?

Upgrading locked abilities would make the game way too easy, especially if you use Yuna's Summoner outfit, because it comes with an Elementaga (I think).

I use a lot of FF7 mods, I cam compile a list if necessary.