Estimate your outage duration
Use the battery's usable capacity, not nominal capacity. For the load, enter the average power you expect the backed-up circuits to draw during the outage.
12.2 kWh available after the reserve, against an estimated net load of 0.6 kW.
This is an energy-duration estimate, not a backup-capability check. The battery/inverter must also have enough continuous and surge output for the appliances you want to run. Solar during a real outage varies with weather, time of day and whether the system can operate while islanded.
How to interpret the result
A 10-hour energy estimate does not guarantee 10 hours of whole-home operation. High-power appliances can exceed the battery inverter's output even when there is plenty of stored energy left.
Solar recharging should only be included when the proposed system is specifically designed to keep solar operating while islanded. For the electrical design questions, read Solar Battery Backup During a Blackout ↗.