Bendis is out of the running unless he was to give up Superman, I reckon. Between both Super books, Young Justice, his creator owned Jinxworld imprint, and Legion of Super Heroes, he has a lot on his plate already.
Williamson would make sense, as his Flash run should be ending soon.
I can see Hickman coming in later, but not in 2020. He's out of the running as long as he's in charge of the X-Men.