3. user is redirected back to site

User never leaves your site. Please test CB Connect or the individual connect plugins thoroughly to understand how they work.

5. user selects a Free plan, fills in the required fields and clicks "register"

There's no fields to fill in. They'll only be presented with a plan page to select their plan.

6. assuming all their data is correct the user is registered and a success message or redirected landing page is displayed.

After selecting their plan they'll need to click FBC button again and it'll log them in properly.

1. I am still a little unclear on what fields are displayed during the step that the user must select a plan to continue, can I have custom fields displayed either using CB or cbsubs?

None are displayed.

2. Will this process work only for NEW users? What about existing users who want to connect through Facebook?

They first login through login module as normal then click the "Link" button to link the two accounts together and they can then use either/or to login to the site. It will not synchronize any fields over as field mapping applies to new registrations only.

3. Does this support Twitter connecting in the same fashion?

Yes.

Please review the below CB Connect information page which details everything that CB Connect provides. As you're a professional subscriber it would do no harm to actually just try it for your self so you may experience it firsthand.

www.joomlapolis.com/cb-solutions/cb-connect