Hmmm... Well she's the only girl in a group of guys, so she's likely to be a bit tomboyish with a hidden girly side, which would show in the outfits she wears when she's alone. So she'd have cutesy girly pjs in my opinion... So maybe something like a layered top look (sorta like Kairi's but more revealing, like a shoulder showing long sleeve shirt paired with a cute tank top style shirt) and maybe this style of capri sweats that remind me of bell bottom jeans from the seventy's. They're really loose and flowy near the bottom like bell bottoms.
