Most excellent story, I particularly enjoyed the characterization of the various characters. The groundwork you're laying for the trio is quite good, and the foreshadowing from the twins was quite hilarious.
In my experience the best relationships are built atop friendship so I don't really see them needing to "get through" that, more along the lines that Harry tends to compartmentalize things, and Hermione has been in the "friend" box for so long that with his loyalty to Luna its conspiring to make things uncomfortable for them both.
Perhaps when he gets to thinking about their sleeping arrangements he'll get a bit of a hint. But who knows? I'll be watching to see how this develops. Hopefully ficwad has an alert function.