Sandy, I am pretty unfamiliar with gluten free flour though I know it can be substituted quite easily for regular flour in many recipes. However, instead of substituting, I would suggest doing a Google search for “gluten free peanut butter oatmeal M&M cookies”. If there isn’t one out there, I’m sure there is something close that would be just as delicious.
Best of luck, and thanks for your question!
~ Lynne

Olympia, unfortunately, I don’t think there’s a way to avoid that. The candies probably won’t melt when baked, but there’s usually a couple that have may when baked. Sorry about that.