I don't think she could squeeze into those-- even though I'd really like to see that.
Rather, those are probably Chen's. Ran's taunting me and daring me to try and take them from her. I guess she goes suppatenko when she gets serious. Or maybe it's just traditional to eat panties while nude. Kinda ironic, in a way.
Hmmmmm... this pose with the bowl and chopsticks rings a bell...
...It's what Oolong uses when transformed into a big robot looking sort of villain in Dragonball around when he and Goku first meet! But maybe it's generic?