Lena/Ian relationship can blow up in like three possible ways, Ian/Holly gets its resolution one way or another, and Lena/Ian/Holly can become an actual thing. I wonder what's your idea of escalation if these are "holiday and chilling" in your eyes..?
By "holiday and chilling" I meant in the context that I don't think 4 more chapters is anywhere near enough to close out ORS because in the chapter 12 we've got, plot lines just started escalating. The escalation being the things you've wrote.
There are many other plot lines that are still ramping up and hasn't explode yet. 4 chapters of ramping up, climax and cooling off sounds like a rush to me.
I think 1 to 9 in general was good. But after 9, i think 10 to 12 the pacing is pretty slow. I think to wrap up everything, ORS at least would need at least to Ch 17 or 18, and that is if Ch 13 pick up the pace. So really, maybe even Ch 20 is more realistic