1.there will be no major rubbing issues, I've got 215/45/17 and I'm dropped just about 2inches on Tein coilovers. you're going to need new shocks in a hurry if you go that low with stock shocks. you can proably get away with out a camber kit, but your tires will wear out quicker. I've got no wheel gap in the rear, and about a finger or 2 gap in the front.

2.b or c

3. another person can help you out on that, I had my coilovers installed by a shop cause I didn't want to deal with the hassel.