You need to move to Eugene. Lots of "Webfoots" around here

I had the idea of pedals keeping the feet straight. And that may help some.

However, different pedals have different amount of float. SPD cleats are rated for about 6° Float.

I believe the Speedplay & Speedplay FROG pedals are rated for the most float (I think the Frog is higher than the standard Speedplay).

Anyway, you might try the Speedplay pedals, and let your legs naturally choose their angle. As mentioned above, the pedal extenders might help with heal clearance.

It wouldn't hurt to also talk to a podiatrist with an interest in Sports Medicine (and cycling). There is lots of good information on the internet, and it is good for food for thought. But for specific medical recommendations, it is worth about as much as it costs.