Figured someone else would have answered already, so I'll chip in, now.
I actually haven't tried it to see what happens, but "Carver V Campaign" was the name for the original retail MC2 campaign, so I expected "Carver 5" to be the updated one, and that's the one I've always used.
The primary difference, if there is one(if not, compared to the retail campaign), is that newer Mechs are used instead of just the same old standbys of each faction. The improved AI also makes it a considerably different game than MC2 retail, though I'd expect if the "Carver 5 Campaign" is unaltered, the AI will still be better.
No idea on the resolution issue.