Never having tried it, I can’t speak from experience, but the second attempt was the one that would have benefited from the gear being up. The gear works better than the speed brakes in the 320. If I’m not mistaken, they crashed about a mile from the runway.
With the absence of the FDR data, we probably won’t know exactly when they lowered the gear, but I’m guessing if they’d waited until ~200ft to drop it, they may have walked away.
That of course assumes the windmilling engines would produce sufficient pressure to lower the gear and support the flight controls. That procedure would take a bit of planning and thought, which in fairness, even on a good day, would probably be difficult under the circumstances.
In my opinion, starting the APU would definitely have helped.