Could someone tell me which crew Rivett is in?
and does he have a dragon, if so what is its name and what type it?
because I've only seen up to the episode "The Prophet's Motive", and I'm writing stuff on it, and I would like to know

Rivett is in the Mechanists crew. They're a pretty secretive crew and are centered around gray draconium and gray bone dragons. He doesn't appear to have a dragon currently, though he claims Libris was once his dragon (in the episode "The Mechanist") and he therefore knows about the Horn of Libris.

How's that? Need anything else? :)