I guess it is possible that they could attack a queen cell, but it's on the method that bees attack other bees, not larva. If the queen cell hasn't opened yet, it is larva developing. the hard part is that sometimes it's too close to the time she hatches. Just yesterday, I was about to move over a capped queen cell and actually realized she was hatching out at that moment, and watched her break free and fly off. No idea where she went, but hopefully it wasn't into the honey super I had sitting nearby for that hive. A virgin queen ought to be able to make it down through the queen excluder though.
The idea is basically to transfer frames of bees and brood, with a capped queen cell, into a new hive. The bees will recognize they are queenless, and when the new queen hatches out, they will accept her just fine, and it will be like a supercedure, or requeening situation. The bees should not fly off like a swarm.
In my case, the bees were queenless. I introduced a capped queen cell, which they should accept that new queen as one they raised when she hatches out. If you were just to drop a queen in a queenless hive, they would probably kill her as a foreigner.
As for CCD. I know that there have been studies out about fungus and virus, but that really doesn't explain CCD. Diseases kill bees in the hive and you will see the dead in the hive, or on the ground in front. CCD behavior just shows a gradual shrinking until there are no bees left.
Bayer makes a pesticide that basically gives colony insects Alzheimers. They can't remember how to get back to the colony. They collect the food, but then wander, so the colony doesn't get the food, and the bee dies from exposure. That's what I think CCD is.
Anyway, regardless of the other factors, genetics plays a big factor. Most people get their bees from Georgia. Those bees for the most part have been vaccinated and medicated so there are no real strong genetics that have a chance unless you follow the medication method. I haven't medicated my bees in over 8 years. Nothing. I've done a couple of the organics like spearmint oil, and some of the pollen patties that I've made just to build up a little, but my main focus is just getting better bees -and that means getting feral bees when I can.
The other thing that's interesting is the size of bees. 100 years ago, we artificially increased the bee size by putting in manufactured comb with a larger comb size. The bees drew out that comb, and since there was more room, the larva took a couple more days until they maxed out their size. The result was a bigger bee that could carry more nectar to the hive.
However, since the bee spent more time in development, that allowed for a larger trachea, which now allows trachael mites to survive. The longer "gestation" also allowed more veroa mites to complete their lifecycle. So, in the end, we have a larger bee more susceptible to their 2 biggest pests.
The solution is moving back to a small cell bee. I've not made the jump yet, but I am starting 2 top bar hives. I also let the bees make as much propolis as they want. It has been considered that the propolis is an extension of the bees immune system, and by our breeding bees with less propolis, we have made them more susceptible to disease, and therfore, we put terramycin in the hives, when it previously wasn't needed.
Most beekeepers would argue with me. But again, I have healthy bees, with 3 supers of honey on most of them by early May and that's after pulling 3 frames each to start new colonies. And no winter losses. I must not be all wrong.