AC coupled backup system design

 I’m trying to design an AC coupled battery backup for an existing grid tied solar system that’s using Solar Edge inverters. I just wanted to confirm a few design parameters. My system is 32 kW. It looks like I would need 2 18kPV hybrid inverters connected in parallel, and at least 30 kWh of connected batteries. I do have a copy of a system schematic using a single 18 kPV inverter. A few questions:

1. Are the component capacities I listed correct?

2. What do I need to know about connecting the inverters in parallel?

3. I have a diesel generator I would like to use with the system only when the grid is down. Can I put this on a transfer switch to disconnect the grid connection and connect the generator in place of the grid input?  If so, what configuration changes if any would I need to make in the inverters?

Thanks in advance