Rather than the idea of trying it to see, I would make other plans. Since one of the concerns might be the loss of BB, I would not want to risk killing a few now as a test. You may need them. For a short term power outage, I would plan to have everything as clean as practical and the water in good shape. I would also want to have all the items in place to do several water changes during the outage if practical. The fish don't need the filters if you keep the water clean and moving. The bacteria should be good for that short time but if you have HOB, pouring water through would help assure this.
The inverter is good and doesn't have to actually be installed, just connected to the car for power. It doesn't need to run full time, just 15 minutes each hour to get O2 to it all would be my plan since it is on hand.