Restricted Cast, who would you pick?

I think we can all agree that Terra, Locke and Celes are kinda of mandatory to the plot. The fourth character could be either Edgar or Cyan, to balance the gameplay ascpect. However, I think you would end up having to to add more skills to each character (like FFIV), because Morph, Runic and Steal are, if not useless, used pretty rarely. Now that I think about it, this is an interesting concept for a hack: less characters, but each one have an extra ability, like, maybe Locke could use Steal and Throw, Terra, Morph and Summon, etc. I don't make idea how hard it would be to code that, though. Also, changes to plot would be necessary, because, right now, I can't think anything that Cyan could specialize except for Bushido.

You could do this if you remapped Item to replace the "Row" command, and made that exclusive to the world map. Here are abilties that could work.

Terra: Fight | Magic | Morph | Lore
I think Blue Magic should be in the game, and it makes the most sense for Terra to have it.

Locke: Fight | Magic | Steal/Mug | Throw/GP Rain/Slot/Sketch/Control/Mimic/Dance
So, Locke's big thing is that his last ability slot is blank until you equip a relic to change it out. The relics could be gained from previous main characters. For example, Setzer could give you a relic that changes your last command to "Slot". This would require some ASM hacking, but is easily doable. Mug and an increased chance to steal I see as being upgrades he gains through storyline events, rather than relics, kind of like how Terra's Morph gets upgraded in the WOR.

Celes: Fight | Magic | Runic | Tools (renamed Tek)
As the actual trained Magitek knight, Celes being able to use the Tools makes the most sense. She can also gain the ability to use Spears, making her a perfect Dragoon.

Cyan: Fight | Magic | SwdTech | Blitz
The combo of SwdTech/Blitz gives Cyan an interesting gameplay loop without breaking character. Do you want to spend time for a surefire hit, or do button inputs for a quick ability?