A1: On the first pass take out every building before the very last house there is one building kinda hidin behind a church take out that one and hit the church too that is one of the upper level buildings even though it is close then take out the last building. on the first pass you must take out all the buildings flashing and dont forget the one that is right there when you first appear do that and take out the non flashing church hiding the second to last building and your golden. on the second pass try your best to hit any thing. on the third pass there will be three buildings left if none were hit on the second however one of the buildings (the closest one is actualy two even thogh it appears to be one. The best tip I can give is hitting the church (which will not be flashing but is kind of hiding one that is) on the first pass and just getting good at the controls and how far shots go which is not as far as you might at first think.

A2: I have the same problem... just keep trying is all that I can say

A3: It is possible, after manny attempts I finally destroyed them all. But there's no reward for completing the mission, so if you never do, you're not missing out on anything.

A4: It's a pain in the back just keep practicing  on measuring distances!