Sure:
1) I will test it. Honestly, I never used channel 6 myself
2) Strange.. Can you try the new beta from the download section?
3) Yes, I need to fix that. When the GPS is locked, the home position is set and all relative coordinates are translated by gluonpilot into absolute ones... In the beta version I only do it when the speed reached 7km/h once (=airborne). But a better solution is needed indeed.
4) Yes. SET_LOITER_POSITION and LOITER_CIRCLE. For optimal use, you will need an XBee and the groundstation. You create a block "LOITER" that contains these 2 commands (+ GOTO to remain in the circle). Press the "LOITER" button and it starts loitering