Hi!
Your frog may be unsocial as it's settling into a new home. Puffing up is it's way of making it's self look bigger and more threatening to any possible predator. White's treefrogs often change colour according to environment and mood, so colour change isn't always a bad sign. Also, they're not very active during the day as they are nocturnal and hunt at night.
Not sure about the spasm, but mine do it when they've just eaten a cricket. It freaked me out a bit when I first saw it.
Hope I've been a little helpful lol