First off I'd like to compliment Celestrata on the RoR FAQ and Q&A, which is considerably more informative than the RoI one.
As for the questions that aren't in there just yet, here's my current best guesses and interpretation of dev-posts:
What's included in the Rohan Expansion Content mentioned as Store purchase in the FAQ?
No confirmation on this one yet. But since it's not called the 'Rohan Quest Pack' best guess is it will be like RoI and include the Quest Pack, the Skirmish Soldier Rank and the non-free War Horse updates.
Are to-be-released-later instances included in RoR web or Lotro store purchase?
While this Other RoR FAQ originally mentioned they'll be free for those who purchased the RoR expansion, Sapience has mentioned this information was 'out of date'. So it's unkown at this point if they're a separate purchase, though it would be a major selling point for a lot of people, so I wonder why they're being so secretive about it.
Will instances X or skirmish Y be scaled to 85?
Based on RoI, most skirmishes will scale right away. Previously scaled instances tend to take a bit longer so the might or might not be scaled immediately, but will be scaled eventually. Non-scaled instances like the Isengard cluster and Roots of Fangorn will most likely NOT scale.
What about PvMP!?!?!
So far this is a topic of deafening silence. I would expect new gear sets, a rise in Audacity cap and based on the previous updates maybe another two MP-class overhauls.