I'm gonna have Yuffie switch to her Kingdom Hearts outfit, just because it's less complicated and makes more sense if she's been influenced by Spira. She'll probably remove the scarf to play Blitzball, but other than that...
Yuffie Kisaragi, ninja extraordinaire! She'll steal your heart... and more! Well, maybe someday, she'll be a heartbreaker. Right now, Yuffie's still rather on the cute side of good-looking, with a mischievous smile, a mischievous sparkle in her pretty silvery-brown eyes, and... well... this girl is just mischief personified! Her brown hair is cut fairly short, but still fairly wild, her bangs falling to one side of her face to about the level of the top of her neck, the rest of her hair cut at about the same length, coming down to the bottom of her neck in a few places in back. She's accessorized with a forest-green headband with long tails that come down past her shoulderblades.
She seems to have assembled a rather eclectic outfit for herself. She wears a sleeveless, midriff-baring shirt of the same forest green as her headband, snugged up around her chests, and with buckled straps going up over her shoulders. Around her neck is a light yellow scarf, wrapped around and with one tail of it hanging over her chest to one side. She wears a pair of fingerless red gloves, with the backs rather baggy and coming almost up to her elbows, with bands of black just under the tops. Coming from under the gloves are a sort of tight black "sleeves", coming almost all the way up to her shoulders.
She wears a pair of khaki shorts with plenty of buttonable pockets; they're actually zipped and buttoned, but still sit low down on her hips, showing them off a bit. Draped over the shorts is a thick blue belt that hangs down some in front. A set of white stockings come to about halfway up her thighs, clinging tight enough to support themselves. Her shoes are low-topped red boots with white soles, looking sturdy enough to stand up to some serious abuse.