Available for Mac?

Doublepost is doublepost.

I wouldn't count on it. Bootcamp should be fine either way, but if you want to see that the game works under Parallels' D3D support (same goes for Linux+Wine users), then the first phase of the beta would be the best time to give feedback on how it runs (or doesn't). Now I wouldn't expect official support, but if you do participate then the devs may be able to squash any critical issues with such setups.