Fronius Symo three-phase solar inverter

Not on its own. Every grid connected inverter has to shut down in a blackout so it cannot energise the network while linesmen are working on it. To keep circuits alive you need three things together: a battery, an inverter with a backup output, and that backup actually wired to a separate circuit board. This family has no backup output, so it will not run your home in a blackout.

That is the standard Australian design, not a shortcut. Panels almost never produce their rated output once you account for heat, angle, dust and cloud, so a slightly larger array keeps the inverter working in its efficient range for more of the day. The rebate rules allow an array up to 133% of the inverter’s rated output, and the rebate is calculated on panel capacity. The energy lost to clipping is a fraction of a percent a year.

You can add one later either way. You can replace the inverter with a hybrid, or add a separate battery inverter alongside and keep your existing one running. A hybrid costs a little more up front, so it is worth it when the battery is genuinely coming rather than a maybe.

Barely. Across reputable brands the spread is under one percentage point, which is in the order of ten or twenty dollars a year on a typical home. Warranty terms, whether there is a service presence in Australia, and which batteries it supports are worth far more than a decimal point.

Your network sets the ceiling. In the ACT that is typically 5 kVA per phase, and in NSW around 5 kW per phase, with the exact figure depending on your distributor and your street. Whether your home is single or three phase is the first thing that decides it, so it is the first thing we check.