Actually, you're wrong on several of those, cause new ALts have been confirmed through Trailers and demos:
Cloud of Dakrness: She's going to have a design where her skin is orange. Direct reference to how she FIRST appears in FF3.
Zidane: Pluto Knight Design.
Frionel: Evidently, he's getting his outfit from the FF2 CG from Origins (much as that doesn't look like him AT ALL)
They can be creative with a few designs too. For example, giving Ultimecia a design that resembles Edea or Adel would be a start, and fitting. Gabranth could easily get away with a Basch-like outfit. And they could also give Kuja an outfit that resembles the Bran-bal Genomes.
And Emperor is, at least for his base design, getting his FF2 Origins CG Coloring, based on the FMV. We don't know if he's getting the Light Emperor Form or not, but you have to realize that it might not be as feasible as you're claiming. Main thing is, it looks completely different, and simply making a new skin may not work so well for something shaped like that. I didn't say its impossible, but its understandable if they don't.
Besides, they openly stated they're trying to be more creative and make the new Alts not as throw away as the previous ones. There's some vague hints that they may even be changing some old, useless alts in the mix.
You're looking at this way too simplistically, is my point. Creativity can be applied, and seeing as they're actually giving Lightning an Aya Brea outfit, even if its DLC, they're very obviously not limited "has this character used this design?"