Too much space is probably the issue but really hard to manage exactly with purchased equipment. For the record, I get comb and brood like most years in at least one or two hives. When they decide they need the space they will build comb in some amazing places. As for the aggression, anytime you tear up comb and expose brood they assume they are under attack and respond in kind. A little smoke around the opened brood should help.

Insulating hives is not really necessary in NWA. I have several hives with screened bottom boards and I usually close those off but I know other area beekeepers who don't even bother.

This is one of my favorites for the beginner. https://www.amazon.com/Backyard-Beekeeper-Revised-Updated-3rd-ebook/dp/B00KJ26FUI