Looks like a cool project! Fish and wildlife paradise.
One thing I notice is the pond banks are very steep, which may be a safety issue. Another is that I can see subsoil layers, are you concerned about leakage through these? I am not a soils expert, and it is near impossible to tell from pictures, but I would think those layers would indicate that a good water seal is unlikely on those sides (sand between layers and so on). If you have clay available, I would reduce the slope of the sides while working a homogeneous clay layer over the sides. Others can give recommendations how to do that.
That is just what I see, though there are experts here that make me look like a gerbil.
Sorry I am no help with stocking plans that far south.
