As I was making resin castings of Monster High Howleen's feet, I started to think that they looked remarkably like Tiny Kitty's feet. So of course I had to check. The first photo shows Howleen on the left and Tiny Kitty on the right. The arches of their feet seemed very similar.
Here are the feet shown with a sole I have made for Tiny Kitty. As you can see, the arch fits Howleen very well and even the length of the feet is the same.
The problem arises when you look at the toes. Howleen's foot is much wider, so shoes made for Tiny Kitty won't fit her. However, I am wondering whether it would be a good idea to make shoes using Howleen's feet, so they would fit both dolls. Some shoes could be too loose for Tiny Kitty, but some models might work. I guess I'll just have to try and see.