1899 - Alan Scott is born.
1916 - 17-year-old Alan enlists in the Army during WW1.
1919 - 20-year-old Alan returns home a decorated war hero & goes to school to study journalism & electronics.
1923 - 24-year-old Alan begins his own radio network.
1931 - 32-year-old Alan finds the starheart, a dense meteor of condensed Oan Energy, and feels compelled to craft it into a lantern & ring & become the Green Lantern.
1939 - WW2 begins.
1945 - WW2 ends. 46-year-old Alan begins restructuring his networks for television.
28 years ago - 52-year-old Alan is flung from Ragnarok more than a decade before the rest of the Justice Society, and is confronted by Rip Hunter, who warns him to stay hidden until the rest of the Justice Society return, lest his presence disrupt the timeline.
26 years ago - 54-year-old Alan has two children with Rose Canton, both of whom he must give up for adoption; Jennifer-Lynn Hayden & Todd James Rice.
11 years ago - When the rest of the Justice Society return from Ragnarok, 69-year-old Alan can finally reveal himself to Jenn & Todd.
Alan Scott presents a massive challenge to our timeline project. While we've crafted our version of the All-Star Squadron specifically so that all the Golden Age characters that have Modern-age children or legacies can exist without disrupting the timeline, there is absolutely no way we can move Alan Scott into that team. He is his era's Superman, the figurehead of his generation. There is simply no way the golden age Justice Society can exist without him.
We had used the premise of the Justice Society being lost in Ragnarok as the explanation for some of their members surviving into modern time, even this creates some narrative issues: We're using the escape as depicted in JLA/JSA Virtue and Vise, and for that to work you absolutely have to have Ray Palmer. This works just fine for the other escaping characters, explaining why Hawkman and Hawkwoman join the team when they do, it simply isn't soon enough for Alan to have adult children who go on to join the Justice Society when it forms in less than a decade.
The answer, then, is for Alan to return to the timeline sooner. He would have to be in hiding so that he doesn't effect time and prevent Ray Palmer for discovering Ragnarok, and that sort of temporal awareness is really only possible with a visit from Rip Hunter, but once that's done, he can fall in love, have his children and be forced to give them up to adoption so that he can keep the world safe one last time.
Admittedly, it's a more complicated idea than we're usually trying to create, but the end result is worth it: Alan Scott is one of the greatest heroes of the greatest generation, and his children grow up to become great heroes themselves.