1) The 2012 exams will be harder for BI people like myself who have very limited experience of the DBA side. I struggle with some basics and will find 70-462 to be a very difficult but rewarding exam.

2) Given the current lack of material I would advise 2008 exams and then 2012 exams. If you make good notes from the 2008 exams you should find a lot of commonm ground. Check the MS site were they list the topics.

It also depends on the reason for passing the exams. If you want to show a future employer you upgrade your skills then get the 2008 exams in first.

3) I think this is the intention. However I would say that MCSA now shows that you have expanded beyond pure BI.