That is a very good idea, using the aluminum's own corrosion to aid in binding PTFE to the pan. A copolymer would probably work better than the blend. The blend woul dindeed tend to phase separate. You see, polymers don't gain very much entropy on blending, so they don't blend unless there are strong enthalpic interactions. There would not be such enthalpic interaction in the blend here, so PTFE and polyvinyl alcohol would probably phase separate.
Copolymers are a better way to go.
Random copolymers have more blocks per chain than true block copolymers, which means there are more ties between the frying pan surface and the polymer layer. Prepare pan by sandblasting. My guess is that if you get a polymer that can present a layer of fluorinated polymer to PTFE, PTFE will stick to that as well. It will stick to the primer layer. A semi-fluorinated homopolymer as you suggest is a good possibility.