1. You can do it anly with buttons not axis. Current implemenation (%P3D%\SimObjects\Modules\Quadrocopter.dll) has registered control properties like "ThrottleSet", "ThrottleRelease" and etc. with EVENTTYPE_NORMAL (not EVENTTYPE_AXIS). You can set you key assignment (Joystick or Keyboard) in Controls dialog form, but not to the Axis.
By the way you can create (code) SimConnect client on C++ that set double values to the "ThrottleSet", "PitchSet" and etc. properites based on you current joystic inputs.