RE: New vs Old Airtronics wiring
Yes to all three.
Awhile back, I sent 20+ servos to Airtonics and they swapped connectors to the Z version for $1.50 each. They also probably will still swap old receivers for new ones at 50% off list. I got two new 8 ch Z Rx's this way for $100. Mostly did all that to regain cross brand compatibility. Airtronics changed over connectors back in '98, so it's been 8 years now they're compatible with everybody else. I've been with them since '84 for the same reason as you. BTW, Futaba still sells their servo's with connectors you have to modify to use with everybody else's stuff. That's like 35 years of doing it different, even at times within their own brand, what's up with that??
Tower, RadicalRC and a number of others have conversion connectors. Cheaper to have Airtronics do the swap.
With the right connector, Airtronics servos work with anybody's Rx. I moved on to JR as well, but I still have 4 receivers and 50 or so servo's I mix & match with the JR 9303.