I remember that getting position of collision was suggested back then, but Ashley said that it isn't that simple, as firstly, there can be many simultaneous overlapping pixels, and secondly, collisions are optimised that way that when first colliding pixel has occured, it conludes that sprites are colliding and stops further testing.
Suggestion about picking: Action "remove object from selected object list"; I had this event where there was two sprites created and after creating action, there was an action that set an angle for them. The first object's angle was 0 and the second's 180. But when the second object was created, the first object was still on SOL and setting the angle at 180 would set both object's angle at 180.