It's all physically wired, no BT or RF. The Arduino gets the servo angle from an app running on the iPad, which sends it through the Redpark serial cable to RX/TX.
I'm ordering a Pro Mini, instead of a Pro Micro, to see if it's just the way the Micro handles the serial connection. If that's not it, I'm stumped. It's still possible I burned out the pins on the Pro Micro with my lousy soldering.