I didn't notice the dude is in an almost 4-head proportion... I first try to understand the shape and form in a geometric phrase then apply my anatomy knowledge to this dude. I refined some features to better fit with the character that I want this dude to have. 3/4 view it seems like ok, but not so sure. Sorry for spending a long time on it, I try to have a fresh eye on it every week.

This is really cool! I like your notes about this character. You have a lot of interesting things going on in the front view drawing that you could emphasize in the side view to improve your design. Firstly, you may want to use a ruler turn arounds. There are some adjustments you'll have to make for perspective but having a trustworthy guide will help you out a lot while making those kinds of decisions. I moved around some of your guys features to match the guidelines that I drew that and that alone helped a bit with the likeness. Secondly, your side view guy's anatomy is very straight up-and-down. I think that concept works with the personality of the character but it may not make for the most interesting drawing. What I like in your original drawing is the wide chest and the tiny legs, so I rotated his ribcage back a bit to put emphasis on his big barrel chest, making the proportions of his top half even larger in comparison to his bottom half. Think about things that you find interesting about this character and his personality and how you can communicate that to the viewer. The 3/4th view will be the most difficult, but once you have a front and side view that you are happy with, it becomes a matter of justifying the two.