Mike,
Welcome to RCU, and welcome back to RC flying!
My opinion on your questions? The only reason to sell the other planes is if money is an issue, otherwise keep them and fly them once you get your coordination back.
a big stik w/70 surpass a P51 w/0S61 and a 1/3 scale Cub w/G62
Do the planes have servos installed? I'm going to assume they're ready to fly except for battery packs and receivers.
The Big Stik with OS 70, needs recovering. Might get $200 TOPS! (You can buy a good used OS 70 Surpass in the calssifieds for $130 to $140.)
You didn't say which P51, so I'll guess it's something like a Great Planes or Top Flight 60 size from a kit. Depending on the condition of engine and plane, the covering job, etc. I'd say $250 to maybe $300 tops. (Unless it's a show plane with retracts, then....?)
The Cub is a bit tougher. If the plane is in good condition with a good covering job, and the engine runs well, etc. then $500 might be possible.
The older radio gear is virtually worthless. Maybe keep one tranmitter as a buddy box, and you should still be able to use the receivers and servos. But you probably wouldn't get $50 for an old transmitter WITH receiver and servos.
Good luck,
Dennis-