On survival: What was your varroa treatment regimen? Or did they starve? Honestly I doubt the polar vortex had much to do with it. People overwinter in plain wooden boxes in Alaska.
On gentleness: Skunks or bad weather can make a genetically docile hive seem mean, but if you still don't like their demeanor this spring, I say off with her head. Your new queen may have mated with drones with aggressive genetics. Requeen, wait a month or two, and see what you've got. A queen from a quality commercial breeder will raise a gentle hive ~90% of the time. Smelling alarm pheromone when you didn't even open the hive sounds pretty bad.
On queen checks: Just look for eggs. If there are eggs, there must have been a queen in the last 3 days. Easy peasy.
On gentleness: Skunks or bad weather can make a genetically docile hive seem mean, but if you still don't like their demeanor this spring, I say off with her head. Your new queen may have mated with drones with aggressive genetics. Requeen, wait a month or two, and see what you've got. A queen from a quality commercial breeder will raise a gentle hive ~90% of the time. Smelling alarm pheromone when you didn't even open the hive sounds pretty bad.
On queen checks: Just look for eggs. If there are eggs, there must have been a queen in the last 3 days. Easy peasy.