Sorry :embarrassed: I wasn't able to access the link, techNOpeasent that I am :laugh:. My concern is that you 'saw' no eggs prior to making the splits. Splits need 'resources' to survive and thrive, brood in various stages, 'some' eggs (if expecting them to 're' -Queen, lots of bees and plenty of food.
"If" those were queen cells from 3 weeks ago….personally I would have waited another couple weeks for any new queens to be mated (seems there are lots of drones in your area based on description) and start laying. Visible larva in various stages indicates a queen was there 'recently' but no eggs shows she's now absent (old queen swarmed? or killed during split) or new one hasn't begun laying…for any number of reasons.
Its not uncommon to have TWO Queens in a single colony in the Spring (a Mother and daughter), assuring for a better colony success 'if' the virgin queen doesn't survive mating and returning.
"Bee Math" is critical when waiting for a new queen to begin her duties. Once the cell has been opened, 16 days after formed, the queen can take up to a week sometimes to mate and return and then another week before she gets going, laying eggs in earnest.
You absolutely MUST find a way to SEE eggs. It is the best indicator for determining whether a queen is present and laying properly. I use one of those 'headband magnifiers' whenever in doubt.