The aircraft was an EOW A 320 and had life vests. The people who are not wearing theirs, are the people who did not watch the flight attendant demo.
The rear slide rafts are useable in a ditching, you detach them and move them to the fwd exits. May be done before a planned ditching.
Very unlikely the APU was running as at the weights and temp involved still would not have been needed for TO performance.
RAT would have deployed if you lost both engines, giving you Electrics, Normal Law and flight controls. Poss hydraulic power still available for flaps with engines turning even if not producing power.
You ditch gear UP in an A 320 and everything else I have ever heard of with retractable gear. The gear was UP in the ditching. Flown both the 320 and the 737 and pretty similar worries to having to ditch either. Maybe plastic floats better though??