I just made these as a breakfast alternative for my husband and even the kids thought they were great and ate a bunch of the mini ones (and hence wouldn't eat their dinner, but I think the muffins were healthier than the sweet and sour meatballs I made!)
I didn't have any soy flour, so I added the same quantity of tapioca flour, but I am guessing any gluten free flour would work in there. And I used guar gum instead of xanthum gum. They turned out just perfect.
I think you could even add some more cheese and some onion or chives in there to spice it up a bit.