1. Might need a new rear derailer... though I'm not certain I know the harris and/or sheldon's website should have the answer.

2. Chain width has more to do with fitting between the cogs on the rear, not the chainrings in the front, so there shouldn't be a problem.

3. The crankarms you have will work just fine with other rings as long as the biopace rings you have are bolted on to the cranks and not swedged, I don't think the 105 would be.

Paul