I had a run with:
Zidane - Overall main character and most leveled up.
Steiner - Strongest character.
Garnet - For healing and summoning purposes.
Vivi - For his black magic.
Ran through the last 3 major bosses with this lineup fairly easy.
I'm a water dude, jet skis, water pools
Surfin' the (waaaave), I'm hurtin' the (waaaave)...
"Oh Yes" ~ Juelz Santana
I do
Zidane
Freya - Dragon Crest
Steiner - Shock
Quina - Frog Drop/Esuna move
Final Fantasies defeated
Playing
I, II, III, IV, IVAY, V, VI, VII, VIIDoC, VIICC , VIII, Tactics, TA, TA2, IX, X, X-2, XI, XII, XII:RW, XIII, XIII-2, XIII:LR, XIV, Type-0, XV
FavoriteToLeastFavorite : VII>X>Tactics>IX>IV>VIII>XV>VI>XII>X-2>XIII>TA2>V>XIII-2>III>I>LR:FFXIII>II