Krung,
Glad to see you back
JFBConnect has supported the new comment module from Facebook (using the href parameter instead of the xid nonsense) since early March. They originally announced the change in February, and made it mandatory in May. We do have the capability to use the xid parameter (in a legacy mode) in case your site has multiple comments that you don't want 'lost' when transitioning to the new system, but it may take a little extra manual configuration to get it working how you want.
As for the demo site, it should be using the new v2 comment module. I just looked at the page below, and it was there. If there was a page we missed upgrading, let us know:
demo.sourcecoast.com/
Finally, yes, all of our subscriptions are multi-site and you're free to continue using it after the subscription expires. For all the friendly details, see our FAQ below:
www.sourcecoast.com/extensions/subscription-faq
Hope that helps, but if you have other questions, just let us know!
Alex