Betsy,
No question is stupid!!! Asking questions is how most of us have learned-please, don't be afraid to ask questions. Plus the rest us can learn something new from others questions.
I have found solid colored flannel at WalMart, Hancock Fabrics and Hobby Lobby especially at this time of year. You could probably use printed flannel as long as it didn't show through the top or backing fabric. If the top and/or backing are a solid, then you would probably not want to use a printed flannel. I usually buy solid flannel then I don't worry about "show-thru" just if the color itself shows.
I have used flannel for pieced tops,as backings and as a batting.
For a lighter weight "batting" I have used a "fleece" batting- it is NOT the fleece that sweatshirts or throws/blankets are made of. I have found it where the interfacing materials are displayed.
As far as the binding, I don't think it matters that the fabric is not flannel. In fact, "regular" fabric might wear better. I've been taught to cut binding double the finished width, fold in 1/2 (long raw edge to long raw edge), press,then sew along the raw edges to attach it to the project "sandwich".
I'm sorry this is a long reply but I hope I've helped & not confused you. :)