It really doesn't seem like anything is happening between them in this issue. Although they do share a moment alone, where after reforming himself from the explosion in the last issue, he starts having trouble breathing. She then takes him into her arms, like on the cover, and gives him mouth to mouth to try and revive him. She then makes a comment that it's a pity no one was around to witness her doing this for him, and he eventually comes through, although he's weakened.
Overall, you really don't get a sense of them getting flirtatious with each other, but you never know... It could happen in the next issue, or somewhere down the line. It might even be with Lady Mastermind, or someone else. The Mystique thing might be a decoy.
And contrary to what some people think, I don't believe he's bi-sexual. Because I'd have a very hard time believing he'd go for Northstar after that whole "death is like a slingshot rock" thing.
...After all, would you date someone that just tried to kill you?
Oh, and yes his hair is still blonde.