I removed the queen cages today, day 3. As you all said, my worrying was unfounded, and I suspect that the group of bees near the entrance were indeed there because the queen cage was on the bottom board near there. On the other hive (after learning from my previous error), I found this hanging from the bottom of the queen cage when I pulled it out:
The bees hanging all over it and working (I inspected closely to ensure the queen wasn't there) were reluctant to give up their work. I got buzzed a few times, but no bees landed on me or strenuously objected to my bumbling interference as I shook them off into the hive.
In addition, they were building comb out of the foundation like crazy. No problems with plastic foundation here, in either hive. They were well covered on three frames in each hive, busy building. I even saw some stored sugar water in some cells. From what I've been reading around here, I don't think I'll refill the feeders until I put the next deep on top, depending on how things in the plant world are going at that time.
My slatted racks and SBB are coming in later this week. I'd been planning to wait until I inspect the hives again in two weeks before installing them, to minimize the disturbance to the hives. Is this a good plan, or should I do it right away?