What is the best way to make Vicks and Wedge into "normal" party members?

I've played around a bit with the ASM hacking, and I was able to get as far as changing the events so that, after encountering Tritoch, you find yourself standing in front of the Beginner's House in Narshe with Vicks and Wedge, and without Terra. That part was actually pretty easy.

But it seems that Wedge and Vicks are not equippable, and I've read that the game has a lot of strangeness with the way the 13th and 14th slots work, often replacing them with ghosts, Moogles, or other guest characters.

So would I be better off overwriting two other characters in the game with Vicks and Wedge, or trying to make the existing Vicks and Wedge equippable and such?

The first route would involve hacking several earlier events in the game, and the initially assigned party, to include the "new" Vicks and Wedge rather than the original ones, and figuring out a way to change the palettes used for them outside of battle. The second route seems like it would be more difficult, and require me to change the way the airship and shops deal with party members.

I won't be using Locke, Sabin, or Cyan in this hack, so I would have no problem overwriting them.

While I'm at it, I was also thinking of giving Vicks a green uniform while leaving Wedge brown, so as to establish one of them as higher ranking and also help differentiate them in battle. Not sure if that would be difficult or not.