A few hours wont be a problem. People have unexpected power outages of longer periods than that without even noticing or experiencing any issues.
You have your battery pump to aerate the water, which is what will be of most concern, but even that shouldn't be an issue for the time period you are talking about. Temperature shouldn't drop too much or quickly in that space of time, but wrap the tank in a blanket or insulating blanket to minimise that if you are still concerned.
If you want to be ultra cautious, then you could avoid feeding for 24 hours before the outage to minimise waste, and double dose prime to detoxify any ammonia build up.
Earlier today i got dragged into a teams meeting for 2 hours mid water change. Half filled tank, no filter, no heater, no problems.