In a nutshell, you canít get there from here. ADS-B in and serial in/out from the SafeFly require 115k baud. IIRC the serial out line for autopilot servo control requires 9600 baud. So the open remaining ďoutĒ port does you no good- though from what you wrote it sounds like you understand that. The Mini A/P technically has 3 serial ports, though one is consumed by the external magnetometer (guessing you know that too). What it needs is 4 serial ports. 3 just isnít sufficient for standalone use.
I suppose what I would do in your case is to connect the servos to one of the open spc ports on the SafeFly and see just how bad the latency is.
I have said Mini AP, the SafeFly and a Sport SX with 5 ports. Even that combo caused me to do some creative juggling to connect everything.
RV-7 Flying as of June 24, 2012
600 hours as of April 9, 2018