I'm not sure why they felt it necessary to hide Grace's actual appearance from William and Gillian, but then it's probably better to be safe than sorry if the Claire form was intended as a long term disguise. Yeah, they're all just hanging out in Tedd's house for now, but what if they saw William and Gillian again in a more public setting later?
I guess I am sure why they felt it necessary. GO ME!
I like that William is an uryuom with physical modesty. I mean, yeah, Uryuoms as a culture don't particular care about that sort of thing, but Will was born and raised IN AMERICA! He been taught that one wears pants in public, darn it.
Gillian, meanwhile, only seems to care because William does. I would question whether she's pointing out William's aversion to it as a way of shifting blame, but that doesn't sound like the Gillian *I* know. Or William, for that matter. These two seem pretty upfront about things.