So Pathing is getting a little absurd at this point.
Here's what I've figured out. You can hit on everyone. Lauren seems to be the biggest hurdle at the moment with the PDA. If she kisses you in front of others, it's gonna be a problem.
But that's only on the girls who are optional. Let me explain:
Right now Chloe is, more or less, scripted into constantly be on the forefront. Yes, you can piss her off by getting drunk, but she pretty easily forgives you. Now, the other girls (Riley, Emily, Penelope, Aubrey) they're all pretty much optional at this point. Riley sees you kissing Lauren and cares about it. Emily might honestly not give a crap. Aubrey definitely won't. But Penelope definitely will.
And so will Chloe. And from what it looks like right now, that will eventually happen. Because this game has made it clear in a few different examples, that you will have to make definitive choices.
Now, you can go down the Non-Kissing route with Lauren, but eventually that will probably come back to haunt as well.
Of course there is the option to not go with Lauren at all, but that still will lead to problems, because one can only manwhore so long in this game before it's going to bite them in the ass.