What do the following comic book character pairs have in common?

The Phantom, Captain Marvel

Buck Rogers, Flash Gordon

Green Arrow, Aquaman

The Human Torch, Captain America.

1) Don't Know - Likley played by same actor woudn't know without Googling it

2) Earth Pilots woke up in another time/place (? Both Played by Buster Crabbe)

3) Both appeared in Smallville also played by Justin Hartley GA (Smallville) AM (WB Pilot)

4) Both Played by Chris Evans