I'm pretty happy and satisfied with this!
At this point, there's really not much room for other interpretation - both parties seem to be interested in being more than friends. Marten may be drunk, but I'd agree with his assessment that he's "a little" drunk. No slurring, no staggering, no tequila monster, no visual cues like lines under his eyes, just drunk bubbles. I'd wager he's pleasantly buzzed, but still completely in control of his faculties and is acting on actual desires. As for Claire, I think Faye may have just given a little nudge to something already there. As careful as she has to be in relationships (platonic or otherwise), she's not going to go off of impulse - if she's sitting on his couch, inches from kissing, she has to trust him implicitly and really want to be more than friends. Plus, she's as sober as a priest.
So, I'm good with them calling it a night here! I'd expect Marten to get a pillow and a blanket for her on the couch (presuming it's after midnight and it's probably safer for her to crash there than for Marten to walk her home), then the two of them get breakfast and talk tomorrow. I look forward to watching the story unfold this week!