Fuel trims are expected to be higher when first started, as the engine will use the last known LTs to run until the STs kick in. Really shouldn't take very long at all, as the EB engines go into closed loop VERY quickly. I start getting STs within 30 seconds (or less) on my NA Edge, so I expect the EB to be same or better.
Definitely top off the coolant first before running the engine next time. You won't know if there are air bubbles that need taking care of until the car is at operating temp though. If the weather is warm in LA, shouldn't take long to get up to temp. Then you can "burp" the system if need be. Monitor coolant temps to see how the car is doing while it is warming up, the stock thermostat is 180F, assuming that's what's in there now. Should stay at/under 200F when warmed up.
Don't know if the O2s need replacing. I am thinking maybe not given the vintage of the vehicle, but you have to be ready for that. Monitor the O2 voltages and the lambda values after starting the car next time. The front O2s are wideband, the rear O2s are narrowband, so they have different ranges. If the widebands drop out completely, you know you have a problem there (sensor or wiring). Prefer the rear narrowband O2s to be in the 0.45-0.6 range, then you know the cats are likely A-OK.