I don't think Sands/LF are plotting together, it would also be a pretty silly twist especially after tonights reveal. I think they're setting up Jon to be the hero of the series. What I saw between LF and Sansa was tension because LF realized he fucked up and saw his picture shatter before his eyes along with Sansa not forgiving him for what he'd done to her and really why should she? Sure he helped out Jon but he should've never sold her in the first place and after the abuse she suffered there she's not going to let that go for the sake of power, nor has she ever really been a power hungry character, she just desired to live good before she realized the way she was living was as good as it was going to get, she knows that now and after all they've worked for i don't see her giving it up. I think the time for political power plays are over. All the pieces are in place and now we watch the game finish and come to its conclusion.