A) Anything you've seen made for BtRL that is 100% the work of members of the new team is now part of Diaspora. Some of that stuff may still appear in BtRL as well.
B) We're rebuilding the tables at the moment. BtRL was pretty close to perfection in my opinion thanks to UT's solid work on the flight physics (and the team's solid nagging whenever he got it wrong

). We might tweak things a little but we're unlikely to make any huge changes.
C) There will be no difference in terms of the abilities of the engine since we both use the same one. However since R1 is based on 3.6.10 while the BtRL demo was based on 3.6.9 you can expect significant differences from that. Improved net code is one of the more obvious ones.
As for other differences, it's hard to comment on what BtRL will be like as my information on that project is now 4-5 months old. We've made a few changes but I can't say that BtRL hasn't or won't make those changes sooner or later themselves. Obviously our plot line is different. Can't say how similar missions based on Hand of God or Resurrection Ship, etc will be since we've obviously got to make the same plot, in the same engine.