[Simple5]

I just bought an e36 as a project car. The car is white, the paint over-all is OK, engine runs good, and found most of the parts used or on ebay. I have a few questions about the body and paint.

1) There are rust spots on the roof and A-Pillar. Can I just sand off the rust and use touch-up paint with some clear to patch it up?

2) The rear bumper (ABS Plastic) is yellowed pretty bad. I tried some Heavy Duty Rubbing Compound on it but it left scratches. Any tips?

3) Where the windshield connects with the hood there is a black piece (dont know exactly what to call it) but the rubber seal is gone and the plastic is breaking off in chips (sun eaten) any way to replace of seal this?

I really don't want to spend a lot of money by repainting this stuff. If theres a DIY method I would love to try it! Thanks for any help given!