I think Ja'mie should have swapped the word "ballsy" for "obvious". I think he came in too late in the game for anyone to be that interested in him.
Demi is utterly fake. Not in a malicious way, but she's like Mike: same script, different cast-offs.
I don't think Shaughna is exactly a natural match for Luke, but I think she's more sincere and maybe he'll go for the vulnerability she showed in telling him how she felt (but she left it too late). The "scene" where she and Mike talked to him after the gym, where he had that just had sex look, was probably the sweetest moment of the whole series.