I used the same materials and followed the same basic steps, but with two exceptions. First, I started out with random shapes that were relatively symmetric, since witches are living humans (unlike zombies and monsters).
When I added facial features and hats, I made each different. No two mouths, noses, or sets of eyes are the same. And I intentionally avoided the the offensive, stereotypical witch nose.
I varied the hairstyles, length, and color. And I used a variety of skintones, leaning heavily on greys like I did with the zombies.
As I was drawing my witches, I was imagining their different personalities. As my mind wandered, I thought how ridiculous (and fun) it would be to choose four of my witches and design a sitcom around them living together in the Golden Girls' Miami house. Speaking of which, have you ever noticed how much Golden Girls merch there is on Amazon (affiliate link)?! It's surprising, yet awesome. Anyway... witches. I had a lot of fun drawing them. I encourage you to give it a go! Like before, it's a great project for someone who "can't" draw.