It could be of her and Tenzin when they were younger, that works for me. Lin is probably getting attached to Tenzin again despite how she wanted to put distance between them because of feelings popping up.

I have the urge to draw Asami fire bending now. I think they could have some fluff with the fire bending...I mean now she could call him Master Mako and he can totally teach her some things. Eheheh. Erm. And yeah the water bending won't happen until Xana and Xano see her grasping fire bending rather well. And I'm almost done with my post, I won't be able to give too much for Mako and Asami as I did for Bolin but I will do my best.