Hey Mag,
Love the work so far 
Criticism wise I think in the confusion look you could maybe open the teeth/jaw a little, perhaps even giving it a little twist off away from the high lip. It’s the sort of opposite-balancing thing that faces do naturally when they lift the top lip I think. I’d also think about a bit more of a squint (outer edges of the eyes and upper edge of the cheeks raised?) to the confusion image as if our Mephistopheles is looking at the object of his confusion 
I originally thought expectant/excited might be a little too subtle but I’ve since changed my mind. I think the character would be restrained in his excitement until it turns to Glee, or something similarly intense. Contextually, I think this is the face you’d see as Mephisto looked down on a great cataclysm about to happen … a sort of restrained delight that threatens to suddenly break across his face into a thunderous evil laughter as the volcano explodes or the antichrist is born etc.
If anything I think maybe slightly raising and turning his head (with associated muscle/skin tautness on the sides of the face) would add a little spark to it without giving the game away. Also perhaps a little flaring of the nostrils, literally smelling the taste of victory … oepnning up his senses ready for the big pay off.
I think the thing to be careful of with the expectant/excitement look is to differentiate it from “reflief” … so it isn’t a a sigh or an “ahhhh”. It should have a little more tightness, something restrained in waiting 
But yeah, all minor crits. I think what you have is certainly good enough for the time involved. Especially considering there’s 13 other expressions to do!
Looking forward to the rest…