I've just done a pretty thorough review of a June 12 split population, and while on June 19 (12 days before today) there were 4-7 capped queen cells, today those cells have been eradicated ... it even looks like the tops have been ripped off. I'm taking this as a hint that the potential queens inside have emerged, or at least one has and has practiced regicide on the others.
Now, as thoroughly as I looked, I found no remaining queen, and (because it's almost certainly too early, using calculations based on Michael Bush's "Bee Math" page), no brood.
A few q's, then, if you don't mind:
1) While it's always possible that she scooted out of sight, might I have missed identifying a newly emerged, potentially virgin queen, perhaps mistaking her for a drone? Would her size increase that much after mating?
2) Would it make sense to drop another frame of brood into the box to give them a boost, and perhaps have the means to raise another queen if they need one?
The bees themselves are calm and orderly, which to me indicates their comfort at being queenright. They're drawing out small cell comb beautifully (in the original hive, as well).
And speaking of which ...
3) In the original hive, I replaced the split frames with small cell foundation. While the bees are drawing it out perfectly, the queen has moved up to the next box, a medium super where there was ready space to lay: it's filled with eggs, larvae, and capped brood. I don't mind that, but would it be in my best interest, once the small cell comb is fully drawn, to move the queen to the deep bottom box, and install an excluder temporarily to confine her there to "encourage" her to use it?