Luigi: 5 might be Mario Bros. boxart Luigi? Wasn't that a theory during Brawl too? What's with the final Luigi? Anybody got any input? Peach: 7 is Fire Peach. Any idea on 8? Bowser: 6 is Bowletta, I think. 7, Boom Boom? Rosalina: 5 is Fire Rosalina. 7 is that weird black and gold from Peach again. Diddy Kong: 4 is DKC2 Competitive? Meta Knight: 7 is Galacta Knight. Little Mac: 8 is Super Punch-Out Guy. Mega Man: 5 is... possibly a lot of things, 6 is Slash Claw, 7 is Atomic Fire, 8 is Thunder Beam.
No way is that Lucina alt referencing Anna. That has to be Cordelia with all the white highlights. The first two colours are based off of Nowi and Cherche, and her sixth is probably inspired by Lissa.
I thought of Cordelia, but I thought in that case the cape would probalby be white. The cape could really be in any colour though, since Cordelia doesn't wear one.
Cherche escaped me. Cherche's hair is rose, while the Lucina recolour here is purple without leaning towards the red side.
As for Nowi, I just forgot that she has a purple cape. Very nice observation you have there.
I think the dev team is just taking some creative liberties with the outfits. The grey on the third outfit is a near perfect match for Cherche's armour. In addition I think the eighth outfit is meant to be a Sumia reference. It makes sense since all of the other colours are from parent characters.
All of Shulk's outfits are based on the party members from Xenoblade. From left to right we have Fiora, Dunban, Reyn, Sharla, Melia, and Riki.