This is really amusing...And hey, they're both a pixel style, so it works
For teleportation, regardless of it being a gameplay mechanic or not, the way it's described "Michael" doesn't seem to make very good combat applicable use of it anyways, so it seems pretty negligible. Also while he does have some proof of Stealth, he doesn't seem to use that amazingly well either, considering his go-to tactic is to blow that advantage and go right for (very slow) chasing.
I know it's at least partly Atari limitations, but this Michael is kinda funny to watch him bungle an attack like that.
For AP, they're likely pretty comparable. Michael easily kills normal kids and a teen(?), while Partygoer can fight 1v1 with zombies that were able to tear through a bunch of partying teens, so casual baseline 9-C on both ends.
Mid-Low Regen for Michael isn't bad, but Partygoer can heal up on her drinks as well, so the advantage on either side isn't as strong as it could be. Plus Mid-Low for knife wounds might not heal the gashing Partygoer did to zombie's faces as easily, plus Michael probably won't enjoy being set on fire by her cigarettes either.
Range flip flops. Partygoer has the advantage when Michael tries to get in, given that she can throw items with that same 9-C strength, but once he's in a knife is certainly better than Party Goer having to CQC. However, if Michael attempts to back off like he does due to injuries, Partygoer can easily pelt him with her range on his retreat. Which speaking of, Michael's tendency to try to back off and reapproach the fight might not work so great in a SBA situation. The Babysitter didn't give chase to finish the job, but Partygoer fighting to win is far more likely to.
Plus, I think there's an experience/skill issue with that too. Michael's a killer, but the babysitter putting up a resistance is enough to get him to back off and retry the situation. Meanwhile Partygoer has been shown having longer fights, and getting into multiple back to back through the night. Not to mention that a handful of zombies jumpscare her to catch her by surprise, but she still fights back decently well, which might be a blow to stealth.
I think this comes down to a mix of Partygoer's versatility, being a generally more aggressive and more combat competent opponent than Michael had to fight in the game, and Michael's standard tactics being flawed for this matchup. Michael won't go down easy, and Partygoer will probably shed some blood before leaving, but I think she has what she needs to fight Michael decently evenly, wear him down, and keep herself alive.