Did you put the additional authorization keys and such that are in 1.0’s config into your wp-config? As far as I can tell, that stuff is new and is the only change I’ve noticed.
Yes.
I tried upgrading to Alpha 2 and that didn’t fix the issue. I also made sure that the new secret keys and other login items in the bbpress config are set — and tried pasting them into wp-config.php, too. None of this seemed to address the problem.