I can see that your design should work, however it seems overly complicated.
Your solaredge system will work with your own microgrid, so you shouldn't have to switch the solar panels.
Turn off your main breaker and feed the output of the growatt into the breaker box (using a generator breaker interlock).
You can go a step further and use an automatic transfer switch, but unless there are critical loads you cannot allow to lose power, or it happens frequently, then I don't think the cost is justified.
Keep you existing system exactly as it is, and add the following:
- Gro-watt inverter
- Batteries
- Breaker interlock
- 2 additional breakers
Use one breaker with the interlock to connect the output of the growatt to the electrical panel.
Use the other breaker without an interlock to connect the input of the growatt to the electrical panel.
Connect the batteries to the growatt.
You could add an additional interlock to prevent the growatt from having both input and output breakers on, but I'm not sure it's necessary. Here's a kit that does this, though, if needed:
https://www.interlockkit.com/product_p/k-9010.htm
This way you don't have to alter the solaredge system at all. When you have an outage, go to the breaker box, turn off the main breaker and the growatt input breaker, and all the loads you don't need powered during the outage.
Then turn on the growatt output breaker, and turn on the growatt inverter. It'll power the house, and the solaredge will come back up and add the solar power to the house as well.
The only thing you need to do at that point is make sure the household is drawing more power from your micro-grid than the solar edge is producing. This can be automated with a zero export rule, set up so the solaredge doesn't push energy into the growatt.