To answer your questions.... first chainline can be determined by putting the chain on your small chainring and the middle cog on your rear cassette. At that point, it should be in a perfect straight line, if you were standing behond the bike looking at it. If there is any deviation, then I would recommend you taking it to your LBS and have them look at it.. sometimes you can make it a bit better.

Secondly, by having a derailleur hanger stronger than ithe orginal will definitely put more stress on the frame.. exactly where you don't want it. I would also recomend NOT straightening it out .. when that happens the integrity of the aluminium is compromised by bending and then again when we s straighten it.

Have you put more thought into the compact crank?