Yes, but removing the pay factor is illogical. It would be a professional job and the pay would be commensurate.
I'd be an ensign, specifically an engineer on TNG and hopefully I get a corny over simplification scene; "Ooh, like catching a fish with a net?". It wouldn't be a career based choice, I'd just be stoked to hang out with the crew for 5 episodes.
Nah, those lines go to regulars and guest stars. At best you might get an "aye, aye sir" or "power levels normal".
Indeed. Best answer. Me, I'd go with the Q role. Couldn't pass up the chance to be flashy, crazy and antagonize a Starfleet ship and crew with my omnipotent powers, especially if it was the TNG crew.
On TOS, a redshirt, because hanging out around the regular cast for 5 episodes would be amazing. Any other series, a Q - because it's more fun and would look better on my resume.
Absolutely Q, then I could fly all over the world forever after doing conventions and signing stuff and snapping my fingers.