1. No idea.
2. I believe not, but I haven't tried
3. Firefox should be in the feed and function, Java no, AFAIK
4. Wifi works with my Ambicom card, but you have to manually connect (scripts make this quite easy). I don't use bluetooth, so I haven't tested it.
5. Kismet works with the hostap driver with my Ambicom card right after putting the correct info in kismet.conf (or whatever the file is), I can't comment on others.
6. I believe you have to restore back to SHARP ROM, then you can restore your Beta 3 image, but the time I tried to do that I had SD formatting errors, so YMMV.
7. No idea
Hope this helps.