1. What is the difference between Velocity Roam and Home Leash?
(copter) Forward pitch stick always goes where the nose is pointed in VR and always flies straight away from the arming location in HL. Pull back on the pitch stick in HL and it comes back to you no matter what direction it is pointed.
2. What is Auto Tune?
(copter only) Revo class FCs can run a special tuning flight that sets the PIDs. Otherwise setting PIDs is more of a trial and error manual procedure. EasyTune is a semi-automated tuning procedure.
3. Is there any difference between the "Manual" setting in Flight Mode and the "Stabilized" setting of Roll / Pitch / Yaw / Thrust to "Manual"?
I am pretty sure there is no difference between setting Manual flight mode and setting Stabilzed1 flight mode with Stab1 set to all manual. I am testing a fixed wing with Attitude mode and I currently have my yaw set to manual but roll/pitch are Attitude.