I'm sorry, I can't find where I've read the specifics, so I know that doesn't help much. But I had read that Minfilia's outfit will be first, and the other Scion characters will have their outfits up for sale later. I can only assume that all the Scions will be given some makeover like Y'shtola had.

If these outfits are too complex to allowing different dyes, then perhaps that's a sign that these shouldn't be sold just to tease players. As Ayame above said, some players play with a color theme for characters, as I do, and if we're going to pay real money for these things, we should be able to color them to suit our own fashion.