For hat use PurlSoho pattern, but in stockinette stitch (for 3 hedgehogs you need to at least co 84).

When earflaps are done, start the hedgehog diagram from the Hedgehog Hats pattern.

After the hedgehogs, decrease by k2tog before markers (markers are placed according PS pattern) every round untill 12 st are left. K round. K2tog round twice. Fo last 3 st and hide thread.