Re: Some basic questions….
1) Yes, this is possible via this plugin – http://www.justin-klein.com/projects/wp-fb-autoconnect
2) Yup, BP offers profiles with avatar uploading / cropping.
3) By P2P, I believe you mean the activity stream. You can disable that in the admin area.
4) It depends what you mean by “simple forum”. The forums in BuddyPress do not offer a universal backend to administrate topics. Also, an important distinction you need to know is BuddyPress uses a concept known as “groups”. You need to create a group before you can enable a forum. This is similar to way Facebook works with fan pages. If you need a traditional forum (with forum categories, admin interface), stick to your bbPress install.
If you just want profiles, you can enable just the profiles component and turn off the rest.
The fundamental difference between BuddyPress and bbPress is this:
-bbPress is a forum
-BuddyPress is a social networking script
I believe it’s possible to have extended profiles and avatars on your bbPress install as well. There should be a few plugins out there that does the job.
Re: future of bbPress – it’s pretty much confirmed that bbPress will become a WordPress plugin some time late this year (in fact, work has begun!). Standalone bbPress will cease to exist. However, there are plans to provide backwards compatibility to the new plugin via an import script.