Yes. (Just that I don't know whether pterosaurs have RT's.)
Probably. However, many dinosaurs have structures that probably served as RT's (think of the complicated bone sheets in ceratopsian noses), and often RT's are cartilaginous and won't fossilize. The famous CT scans of theropod skulls say nothing IMHO, because of crushing and poor resolution. BTW, elephants don't have RT's, and there are several other complicating factors that have often been reviewed onlist.
Of course, and vice versa. The air-sac system even implies that endothermy is a synapomorphy of Ornithodira or so (if it is monophyletic).