Solar panels and batteries as primary, grid as backup with auto transfer switch
Sounds like a totally custom system that you will have to design and implement yourself.

If I lived in AZ I might be tempted to install a solar water heater tied to the existing water heaters to start with. Keeps you from having to backfeed the grid and get crossways with your utility.

Another thought is to add solar panels tied through MPPT's to secondary heating coils in the existing water heaters. Using straight DC instead of changing to AC will save you ~15% of loss through an inverter for no reason since resistive heat doesn't need AC.
https://en.wikipedia.org/wiki/Maximum_power_point_tracking

With either of these methods you can use the water to store your heat / power instead of batteries or the grid.

You sound like you have thought about this for a while but make some small investments first and see if you think they are worth it before proceeding. You may be very disappointed if you are not realistic with your calculations and goals.

Happy Tuesday!