Drones also maintain the temperature of the nest/hive.
Additionally, carpenter bee drones defend the hive (although they don't actually have any defences, and therefore do this by repeatedly bumping into the adversary); and Asian honey bee drones help to kill murder hornets, by enveloping them (alongside other bees) and essentially cooking them to death.
No they're not, that wouldn't even make sense. If all individuals of a species are of a single sex, there wouldn't be male and female, they are hermaphrodites. Bees reproduce sexually.