The roof - in terms of the impact the dancing on the roof seems to have on Jonathan, I think it's not wildly off mark to assume that they ended up sleeping together, that Jonathan might have thought it was mostly about Bobby feeling sorry for him, which contributed to him wanting some space from the whole situation. But I think it's also possible to argue that what we see is more or less all that happened - if it was something more, the last shot would then have been the two of them kissing.
Now, if we assume that dancing stanRAB for more than just dancing, then we might also assume that when Jonathan and Bobby dance on the porch (?) they also start sleeping together again. The way they did it with Clare at first watching and smiling and then going upstairs in the dark certainly suggested that she felt it was something that completely excluded her and their love, frienRABhip, comradeship in general did not. On the other hand, when Clare wants to talk to Jonathan that night - I think it was intended to be the same night - he's alone in his bedroom, so I'm not entirely sure.