It is settled who is in, just not who plays whom. The options right now for BOS are CLE, NYY, and TOR (in alphabetical order). I don't know all the odds for this. TOR must have the edge over NYY as they own the tie breaker. So if both win or both lose, it is TOR. Of course if TOR wins and NYY loses, also TOR. To me, that seems like 3 out of 4 outcomes result in TOR winning the division and NYY playing the 2nd wildcard.
BOS will be the 2nd wildcard (5th seed) with a win or a CLE loss and play @NYY or @TOR. It has to be that both CLE and DET win (meaning a BOS loss) in order for CLE to win the division and DET to move up to the 2nd wildcard (5th seed). In that case, it would not matter how it works out between TOR and NYY, BOS would play @CLE.
I don't think it really matters to BOS. They are either @CLE or @NYY (most likely). For DET and CLE, the difference is playing at home or playing on the road. If BOS beats DET, they are the 6th seed and on the road no matter what, vs. CLE. If DET wins and CLE looses, then DET wins the division and plays CLE at home. DET wants Skubal for game 1 in any case so they are not starting him, but should otherwise try to win.
TOR is starting Gausman (or at least that is what is posted right now). So best case for BOS is TOR losses to TB and BOS wins to secure the 5th seed, goes to TOR, but doesn't have to face their ace (Gausman) in game 1, and maybe not at all.