[The Fancy Pansy]

That all sounds like it should be okay (assuming the pumpkin is JUST pumpkin, it's fine). BUT, the GF flour mix will not make a decent pie crust if substituted in a regular recipe. I can guarrantee it. Find an actual GF pastry recipe online. Pie crusts are hard. GF Pie crusts are....well...they take patience.

Try looking over at the livingwithout.com website. They also have good basic info on GF/DF baking and hidden sources and such.