Crashes

[Splute]

How would you call these:
1) A1 attempting throw-in in front court. Throws deep, offline, causing A5 to run to attempt a catch and in the process B5 and A5 colide, while A5 is attempting the catch. Is there a foul on B5 or is it judgement based on each players position at point of catch / crash (ie: no call and play on)? Could there be a foul on A5? Does the defense have the greater responsibility for contact?

2) During rebound, ball is tapped into deep frontcourt and A1 & B1 colide hard while attempting to retrieve it. Is there ever a call in this situation?