Rollling Man: Don't forget that the hook allows for the character to have helped the Vashti as well as having been helped by her. The salsham'ai are quite affable and kind people on the whole, so perhaps he is connected to the Vashti through a shared good deed.
For salsham'ai characters, there are a couple of feats that didn't make it to the PDF. Enhanced Camouflage means that the camouflage bonus is the same no matter what the background is. Multidextrous removes some of the penalty for using feet for fine dexterity.
Blackrat: Certainly the first meaning of the Cult of Beauty, that is young rich folk obsessed with looks, is possible for PCs. The other type, murderers of the aesthetically offensive, would probably not be PC material (although I'm not averse to a character slipping to the dark side).
Shayuri: Officially, no. However it strikes me as a fairly narrow ruling so I'd say yes. Nai-nek-chai, with their spirit ancestry, ought to have a touch of the magical about them. Note that casting spells would come under 'not normal behaviour' for anyone closely observing the animal!