: Also, assuming there's even theater support, will we be able to rewind
: campaign footage?
: Halo 3's theater might answer this question, or at least give decent clues

From what I know, The universal UI won't allow for anything less then for all games to have similar experiences from campaign scoring to theater. while while H1/A and H2/A don't have theater mode (due to them being old engines) 3 and 4 do and if ODST did as well then they should implement it pretty easily and should have all the same features across the games.

: And will ODST be integrated into the existing party/menu system, or will it
: be a separate menu? It would be awful suspicious for there to be hooks
: built into the game if the game wasn't planned to be paid DLC from the
: start...

It should be all the same thing, thats what the Universal UI was made for.

: Which reminds me, since ODST used Halo 3 assets, will this be true of the
: Remaster as well? It might cut down significantly on file size, but if
: that's not the case, could ODST be released as standalone DLC (similar to
: Infamous: First Light)?

I think it'll get the same treatment as 3 and 4.