Seconder from above: I can see any of these reactions from John working. I can definitely see him being oblivious and simply going along with it -- or having been aware of it since the week he moved in. In the case of the latter, I do think it could be made very believable for him to be a bit of an arse about it some days, especially when Sherlock's choosing to be bitchy. John has a history of not putting up with Sherlock when he's throwing one of his fits.

In the end, of course, this is left up to the filler (so I'll shut up about it), but I am pleased that the OP and I are on the same page.