Thanks for the input everyone. There is one open queen cell in the hive on the side of the frame (open--I may have mistaken it for a practice cell as I thought it was unused). There's a solid 3 frames of bees (it's a 5-frame NUC)...they were a winter removal I was going to upgrade this week 2 frames of stores and 1 frames of eggs and young larvae only...rast, there's no capped brood. It does sound like a supercedure has possibly occurred. I think the lack of capped brood and multiple eggs in many cells made me think they went queen less (maybe they were for a short period) and so I thought they developed LW, but indeed, as you are all leaning, I may just have a new queen who needs a little more time and support.
I had not given thought that it may be a recently mated queen--I didn't realize that they may overlay in cells as .30, BF, CB and HP have noted as they get revved up (and the workers prepare more cells).
Jim, I've got about 2/3 of my queens marked now. She wasn't yet so I don't know if it's the original or the daughter in this case. I have a queenless swarm in the apiary right now that I obtained the same day when doing inspections (the homeowner had hosed the swarm and then called me for help when they all wouldn't leave...ugh...it's about 1lb-1.5lbs so it would be a nice little boost and mutually beneficial), so I'll likely upgrade them to a 8-frame hive and merge them to give them boost in numbers as Jim suggested while they get the queen settled into laying.
Thank you all for your knowledge and insight. Will keep watching the thread--a great leaning one for me.