I will try to help.
1) Yes play BI. it is quite different to R:TW as there are different victory conditions for each faction and very different styles of play.
2) install patch 1.6 and player1's bugfixer, there is also at least one allfactions mod that is available but you won't need that as most of the factions are available from the start.
3) there isn't an RTR for BI yet you would have to check in the modding forum for news about that- I think there might be a darth formations mod but it might not be updated for 1.6.

Enjoy- I know I did