beard, mustache, whiskers
鬍 centers on facial hair: beard, mustache, and whiskers. The meanings are all specific types of hair growing on the face.
鬍 combines 髟 (hair) with 胡, which likely contributes the sound. The character is used for facial hair, fitting the hair component.
The top part 髟 means hair, and the bottom part 胡 looks like a face with a beard. Picture a hairy face with a long beard and mustache.
For コ, imagine a koala with a big bushy beard: koala -> コ, and the koala's beard is the 鬍.