I have wild flower borders in my gardens and a couple of lavender gardens, having lots of flowers right next to the colonies is great for pollen and honey production, the supers fill up very quickly and the lavender honey is divine, I also get to make lavender pot pouri once my bees have finished with them..

Seems corgettes are a good source of both nectar and pollen

The best thing to do when you take out a split is to put all the frames together in the original hive and put the foundation or empty comb frames that you are putting into the nuc on the sides (6:10) is where I'm talking about.

That first nuc nearest to the camera up you split looked to have far less bees compared to it's neighbour coming up to the top. So with that queencell being capped I think you were too late and lost original queen to a swarm. Heard it's better to requeen with swarm cells rather than emergency queencells as they will feed older larvae so the new queen will not have been fed as much royal jelly so could be a lacking in quality.

To answer you queen question. You will only get out what you put in