Is this aggression towards a caged queen?

[Kazzandra]

Yes! Great news for you! I need to go into my queenright colony and get one more frame of eggs for the queenless colony so they can build a new queen if they need it, just in case I have the same experience you did-- a queen emerges, something goes wrong, and they need to build another cell.

[johnblagg]

I discovered that is also the best way to check and see if you have a queen as well....they will stop building queen cells with larva in them when they have a queen ...a queen cup but not a actual cell.I am going to add a frame of brood again the middle of next week just to boost the population a bit more.I placed the last brood and eggs in the upper deep just so I could check for queen cells easier. The lower deep is now empty brood comb ready for the new queen to start laying in soon.

[Kazzandra]

Update:
Well, no sign of the queen or of any brood in this hive today. It makes no sense, unless maybe the returning virgin in the parent hive challenged and killed the mated queen and left. The bees are calm and gentle, albeit probably about thirty percent drones (the comb that I used for the split was from the drone laying queen they superseded...), and I made sure not to carry any workers in. They seemed really excited and accepting. I don't know what went wrong. Even made sure to keep them fed during this all, and they still have three combs of honey.

The parent hive from which it came is still aggressive. The frame of larva/eggs I gave them is now all capped over (3 days?!? Some of those larva were really small... or maybe they ate them?!?), with no queen cells, so maybe they're queenright. I don't know. I figured by bee math, if their virgin returned, she would be laying by the 14th. I don't want to mess with them-- just going into the top box gets lots of angry, pinging bees, smoke or not.

This sucks. If just one or the other would take a queen, I could combine them.
Going to pick up a random queen tomorrow and make a push-in cage. Anything's better than nothing. Otherwise, I might offer the bees to a local beekeeping place to shore up weak hives for them...
It's getting way too late to be playing with this fire.