@ r. taghwaei: Thank you so much for your kind words! 
@ Shepard. B: Thank you for the feedback! I definitely agree about the mandibles/teeth. Part of them not blending well is intentional (because I want to leave them as seperate geometry/subTools that can be printed individually in addition to the head; so that they can actually be placed and glued into the head as seperate components for a 1/6 figure project
Here’s a more realistic render:
As far as the head width is concerned, after looking at a ton of reference pics, I really think I finally got it right
It really was tough to nail proportionally. But the head is at it’s widest at the cranium and lower jaw (for the original Predator design). If I make it any wider now, it just looks off and funny.