Not true! the blades do not have to stop in midair, I have been in full no power auto-rotations in a Sikorsky CH-53 from 2500 ft where the pilot never applied power to the engines.
Aircraft attitude and rotor speed make for safe auto-rotations.
This is correct - blades reversing direction is false.
Clutch between engine and blades must be dis-engaged so blades can rotate from speed of air passing through them.
Then the rotating blades become sort of like a poor version of wings that the copter can sort of (not really) glide under.........they don’t provide lift, but reduce the rate of fall.....