If it is indeed the new timeline, then I imagine all you'll need to know is that the heroes have been around for a good long while.
For everyone. Perry would either be dead or there'd have been a previous Daily Planet boss before him.So, in simpler terms with crises they kept starting all over again, even if they started way back. Is it for heroes alone or for other characters as well? Is Perry White 100 years old?
Not sure if that'll come up in this version of it even if the pieces are there, but yeah that was an idea in Superman 2000.This could have come up. But i recently heard about Superman 2000 in more detail. One of the ideas was that the JSA act as a sort of John the Baptist. They did their job. But their part was over. They helped groom Superman who was the real deal. Like Jesus. Parallels aside, the idea was that Superman is touched or inspired by the older generation of heroes in some way.
If you want some totally unfounded hope, Mark Waid has been recently showing up on DC interviews talking about his work, and he said that he's currently doing a big classic Superboy reread. If he were by some chance to come back to work at DC, he could be working on doing Clark Kents past a Superboy while Bendis does all the present day stuff with Jon (all assuming 5G of course).
That would probably be one of the bigger crowd pleasers and help 5G go down smooth. From there one would hope that he'd then stay on for Clark as Superman stories set in the past.