A and C,
I haven't, because I thought maybe the engineer would be the best person to do that. After all, I was basically a spectator.
The engineer has now found the cause of the cause, as it were. Apparently water caused the corrosion, due to a drip in a particular place...no, I don't quite understand it either. He said the starboard aileron is fine after all, and that the aircraft as a whole has remarkably little corrosion for its age, and considering it's always lived outside. I realise this still explains very little, but that's what I've been told.