You have the concept down pretty well it’s just lacking a bit of form underneath. If you look at your 3/4 view your midline of the face is going straight down rather than following the circle of the skull before it turns down. This gives you a false sense of where the hair lays and it tends to put the nose too close to the face. The other 2 aren’t bad. As for the hair and hat, just try to remember where the hairline lays on the circle/skull. The hair needs volume and should sit off from the skull which in turn will raise the hat to allow for that volume. Hope this gives you some structure to practice with the loomis method and placing features.
Wow, thank you so much for the feedback, it's really helpful! I understand it better now.
Awesome, glad I could help.