Pattern is charted and written.
The Sequence hat is worked in the round from the bottom up.
In the pattern the beanie uses Charcoal as Color A and Gamboge as Color B. This is reversed for the slouchy hat (top photo), which uses Gamboge as Color A and Charcoal as Color B. By reversing the colors I was able to knit both hats from just 2 skeins of yarn.
To acheive finished sizes between those listed try adjusting your gauge. Working with a 6-st per inch ribbing (vs the 5.5 in pattern) will result in a forehead circumference of 16 (18.5) inches. A 5-stitch per inch ribbing will give you a finished forehead circumference of 19 (22.5) inches.