there are a bunch of threads out there about this bug.
Sleeping 24h sometimes works.
Fast travel to sanct and back sometimes works.
Shooting the militia guy in the head till he goes down and resets sometimes works.
When I glitched, none of these worked, even using console commands didnt really work, and left me stuck with a companion I didnt want.
I had to reload before the attack to get it right. worked fine the second time. Lost a couple hours, but it was that or not progress the quest series.
there are a bunch of clusters some up by each destroyed artillery platform it could be you missed one I'm not sure I had some minor problems w/ that quest
you may be screwed, you can try the things I mentioned, and if you are on PC you can try some things on the console as well.
I do know that the eggs are a red herring. When I redid it without it bugging, the quest completed with several unresolved egg clusters about the place, which I cleaned up after the completion.
I think it breaks from something about the queen being triggered before the eggs are marked cleared.
I decided that losing a little time now was better than sitting on it and seeing if it gets fixed later, as I wasnt about to start over and I really wanted the castle, and I really didnt want preston following me around the rest of the game.