I don't think Qarr's a familiar. Everything about familiars is keyed off the master's level, and Qarr has his own class levels in sorcerer and everything. I don't know, though. Would his HD change upon becoming Zz'dtri's familiar? Would Z'zdtri notice an empathic link or absence of one?

Kish is definitely right about Celia's dress, though. It does not cause Feeblemindedness. In that same comic Celia and Roy make a bunch of other jokes based on applying D&D rules to romantic interaction. In fact, it would completely deflate Roy's compliment/joke if her dress actually forced a saving throw, as it would be not hyperbole but simple description.