Even if you put in feet holes, it doesn't have enough room for her to move her legs, which means she would be hopping -- really not safe. Could be fun for TV time or bed time, but I really can't see this as a good idea for children to be walking in this. It would be the equivalent of tying their legs together.
What about taking the top of the pattern (I haven't seen it, so I assume there is a top & bottom -- it not, you'd just roughly cut it in half) and using it as an applique on a regular bed quilt?