While I'm generally pretty good with Asian awards, I'm not all too familiar with a rounting via Europe, but here's what I do know:
1. I believe it works for most destinations.
2. Yep, you should be able to stop in Europe or Asia.
4. It's always one or the other, never both.
5. Polar routes are considered Pacific.

I might be wrong, but I believe the only time you can do this is if you're starting the east coast where you're not adding 2,000 miles on just to get to the coast. I believe then they can sometimes be within the MPM, although I'm still not sure how exactly they do it, since there's more to it. Sorry I couldn't help more!