Samantha : Ends up with Monroe the badass
Monroe : See above
Ashley : Hard to say. Part of me wants her to finally see what a good guy Luis is, and part of me doesn't want her to fuck him over (which I honestly see as inevitable), but meh, he's a big boy and can take care of himself. I honestly don't think she's got a happy ending ahead of her unless something drastic happens, like Luis breaking someone in half for her or something.
Luis : See above / he stays single / hooks up with some rando from town.
Emily : Happy ending
Japanese Doctor : I'm biased since I have a real thing for tiny gorgeous Asian girls...but yeah, you aren't wrong, she's waaaaaay out of the MC's league.