Re: There's got to be a queen in there after all?
If they swarmed 30 days ago, your current queen was probably an 8 or so day old larva. She hatched 8 days later. Then it took her roughly 2 weeks to mate and start laying. It could have been as much as 3 weeks. So, right now she's only been laying eggs for about a week.
Give her some time, she might just come around.
Also, that cell is just a place where they had extra space and decided to do something with it. I think I would just thump it off next time.
Very nice pictures!
Try it. What could happen?