Kaje's stuntplane can use the propeller animation with very little lag when moving and not moving, the same would work for the wings.
The size of the dragon shouldn't matter too much. It would be best to keep it about 1.5x larger than the Jeep, so it isn't too small but will actually 'fit' compared to a Vehicle Spawn's size.
Shooting is easy, mount a weapon to its mouth and set triggers etc. when you left click or press Jump or whatever.