Legends of Tomorrow recently had an episode where the team gets trapped in Star City during 2046. In the episode it is said that John Diggle Jr., the new Green Arrow is consumed with grief because he couldn't save his father. It has become no secret the top two contenders for the grave are Captain Lance and Diggle. However, John Jr. is consumed with grief because he couldnt save his father, however, he hasn't even been born yet on Arrow. Even if he is somehow born before the end of the season there is no way he'd be able to save his dad because he's a newborn. So if John Jr. is so upset because he had the chance but couldn't save his father, than it can't possibly be Diggle in the grave. And I am aware a few of you might say "well Rip said it was a POTENTIAL future"! Although you are correct, the very being of John Jr. wouldn't change, meaning Diggle isn't in the grave.