As usual the answer is "probably no". I mean, practically the right combination of flags and counters would always be able to reset to a certain point - but as you said, many other flags and counters are affected and it either resets (if you're lucky) or completely crashes the game logic. You may try around some more but it most certainly would indeed be easier to just start over. For the record: I have had quite a few playthroughs and consider myself quite knowledgeable in the intricacies of this game, and soon I will start over because I once again botched Emma (curse her) ... Luckily for me, I enjoy the ride maybe even more than the completion at the end, however, a couple months of a break don't hurt maybe.