Use the middle one for feeder and cover the other with a piece of plywood.
I fill a plastic takeaway box with fondant and put it above the hole closest to the brood in winter, the other can be covered with a bit of ply then also. Probably allows some ventilation too
but its likely there is some heather honey in there which won't help with spinning them out on thin unwired foundation. I would use for feeding (nadir it).
on the drones in the super problem, how did they end up in the super? the queen excluder should stop them getting into the super.
I'd imagine it works along similar principles as this, longer and lower temp achieves the same result:
https://www.amazingfoodmadeeasy.com/info/sous-vide-safety/more/sous-vide-safety-salmonella-and-bacteria
here's the streetview:
https://www.google.co.uk/maps/@50.4949436,-3.7774397,3a,60y,73.72h,78.1t/data=!3m6!1e1!3m4!1sWzJQEKTLCNS5azc0d3xU-Q!2e0!7i13312!8i6656?hl=en
very similar to your last picture:
some bushes growing over the walls
i put fondant in rapid feeder (took out the clear plastic cup bit) above crown board in an eke, insulation above that. No drips and they seem to be accessing it ok. They'll possibly fill it with brace come in spring though...
I believe it went under the hive, this was the thread:
https://beekeepingforum.co.uk/showthread.php?t=42599
looking at the broodminder though it looks like it only goes under the front of the hive so obviously does the multiplication to get the total weight itself.
unless you extracted each hive separately and cleaned the equipment between each extraction that's a potential way to spread disease between your hives
you probably could have done a split earlier in the summer.
Bee population will be decreasing from here on so the overcrowding problem should be resolved...
Does the shape look similar for other days or is this an unusual one?
5am is close to sunrise?
Could it be bees collecting water first thing to dehydrate after the 2kg drop off overnight in the hot weather?