Hmmm, that IS a little strange. My front tires wear more or less evenly on the edges, it's the rears that seem to wear out the inside edge faster. Your alignment specs seem to be OK, and with only a 1-inch drop (about same as mine), you should NOT have problems like this.

About the tire size, you're pushing clearance limits with that offset and a 225 tire. I'd go with a 215/55/16 tire, which the W210 used on a 16x7.5 wheel. A 225/50 should work with fender lip rolling and the spacer kit up front though.