No they do not. Beavers are not capable of echolocation, which is the practice of using sound echoes to locate and identify the environment.
However, beavers do use sound as a defense mechanism. When threatened, the beaver will dive into the water while slapping its tail hard on the surface. This makes a large booming sound that may scare the predator away while simultaneously alerting other beavers in the area.
No, they do not. Instead of hibernation, beavers like to accumulate piles of sticks and logs in their natural habitat (ponds)… this allows them to eat the underbark while snow can gather on the top of the pile. This also prevents the water to freeze around the food pile, helping beavers to breathe.