I like 3# a lot, and the Wheatley looks pretty solid to me; the main problem I see with him is the lineweight, which I think you could improve on in general to convey proximity and lighting better.
It's clear throughout where you did and didn't use 3d-construction, like with 4# and 6# where the fish guy's arm is pancaked, and the folds of cloth are sorta just flat shapes with wrinkle lines inserted instead of planes that bend and drape around an object (idk if that's the exact way to describe or think about it, but it definitely could use more form).
Overall good and fun sketches that show a lot of progress and study of fundamentals.