Thanks for the advice.
We just checked the hive again this weekend. I didn't see any more eggs, or a queen, but did see lots of what I think is drone brood. Most of it is large and extending out from the top of the frame. There are also a few bulging out, throughout the frame. This makes me think that it was laying workers. Should I wait longer to know for sure?
We did take the sparsely-filled top box (1/3 drawn and little honey) and added it to our healthy hive that had 2 brood boxes and 1 honey box. We mostly did this to add another honey box to the very-productive healthy hive, since honey is flowing and we'll be out of town and unable to check on them for 3 weeks.
Still just wondering if I should combine the two hives in a few weeks...it's starting to get pretty cool up here (lows in the 40s).