Can you post some pictures of the brood combs? Your #2 above is a 99.9 indication of being overwhelmed by spiked varroa mite infestation.
Saddened to say, but this is a very typical Fall varroa hive crash type scenario. The real world varroa test in the North, in BC, is if you had a terminal level mite problem you know for certain in October because the hive is dead. You will know you had damaging level mite problem when the hive is dead in February. If they make it to April, they may still have been weakened by mites but will likely survive the summer and will crash the following September/October.
What did you do for mite checks and treatments at about the middle of August, Au 15-20?
Get some sweezers. Go picking at the capped brood cells. Carefully open the caps, grab the head and slide the bee out. Look on the butt of the bee and in the bottom of the cells for mites. (Provides definitive confirmation)
Take a brood comb. With a bright light or the sun at your back. Tip the top bar of the frame away from you to look at the top wall of the brood cells. Do you see specs of saltlike grains stuck to the top walls? That would be mite fras, mite poop. (Provides definitive confirmation)
Have a close look through whatever dead bees pile is on the ground or in the bottom of the hive. Look at the wings, specifically look for thin wrinkled and/or warped wings. This symptom is named and known as deformed wing virus, look for it in the dead bees and also in the live bees in your other hives. (Provides definitive confirmation). Anytime you see DWV in the bees, treat the colony immediately. Although when DWV is present significant damage has already been done, means it is usually too late to save them. They are pretty much the walking dead when you see DWV.
Also, somewhere on here at BM we have a link of a presentation I made up from 15th members hive here a couple years ago. May be worth looking that up as a reference.
Finally, be careful with moisture ventilation advice and types of equipment. Some , alot actually, is just not applicable for use as you go North. Many of those pillow box type setups end at stressing and killing more hives rather than helping them. A hive that is struggling with moisture or ventilation is quite simply put - sick or not strong enough for the space they are in. Diagnose and treat their ailments or/and reduce space, reduce hive size.