Hi Arran,
You're pretty much on-the-money with your character assessments.
With regard to the pace, that's actually a plot point in itself. Alex goes after what he wants, Harry's hormones kinda cloud his thinking, but what happens once the initial hormones wear off? What happens when Harry starts to see the reality behind Alex's social media persona? What happens if Alex's relationship status no longer matches the 'straight and available' image that he conveys to girls on Instagram?
That's kinda the 'different direction' I'm talking about. This story was gonna be a series of steamy one-shots for Nifty, but now my characters have emotional complexities. I know what I'm going to do with those complexities from a narrative standpoint, I just didn't expect to be going in that direction when I started