1) Yes, any feature upgrades to JFBConnect will be released to users who have purchased the component. v2.0 (RC1) was just released which is our first step to adding a lot of the user creation and automatic logging in features that users requested over the 1.0 Version, and any of those users can now see this (and future 2.0 releases) in their download section.
A caveat to this is Joomla 1.6, which adds a lot of user management features. Depending on the effort to re-work the component to work with that, a version for J1.6 may be a separate release.
So, in short, feature upgrades will be free to current customers for the foreseeable future. Support will always be available for our past works though.
2) It's on the radar. After a stable release of 2.0 which allows Joomla user creation and automatic Facebook log-ins, we plan to work on whatever features are requested. Currently, JomSocial people seem to be the most vocal
Suggestions are welcome.
3) Not yet. We have some test modules we've created and another author we're working with to generate new features (such as status updates and more profile integration), but no announcements yet.