Welcome to the challenge your stuff looks great!

I'm still new to organic modeling but here's my advice on the squareishness. It looks like the cheek is flat on the side as it leads to the front of the head. Maybe try rounding out the side of the cheeks. I imagine this will round out his head without getting rid of his Heroic/Adventurer jawline and marring his rougishly good looks: I've included a picture of the area I thought might help.

Hope this helps!