From what I can remember it won't be an easy task. The stator is not very thick and runs with little clearance between the magnets, it will need a fairly precise mould to make a replacement.
The one I took to bits ( long ago) was single phase so the winding will be simple and there is not much room in there for any sensible size wire. You can check the magnet with a screwdriver or something, my suspicion is that it is 8 pole so knowing the magnet poles will help you sort the number of coils.
With care you should be able to find one intact coil with a bit of excavating and get turns and wire diameter.
The one I took to bits turned out not to be faulty, it was used in an urban environment and never saw enough wind to reach cut in, it looks to be reasonably fast at cut in but I never measured anything. At a guess I would think cut in was over 400 rpm, if you could measure that from a working machine you would be well on the way to designing the coils even if you can't measure anything from the original stator.
I don't think you can melt the original stator but it may soften a bit to aid excavation.
Flux
