Do you remember that in JSA, the Gray Man awakened Sand Hawkins to his prophetic dream power, a gift from Wesley Dodds (the Golden Age Sandman) ?
In his initial prophetic dream, departed JSAers gave him various warnings.
Hourman's (not pictured here) clearly predicts Sand's challenge at Roulette's House. And Dr. Mid-Nite's prophecy (also not pictured) concerns the battle against the Dark Trinity of Obsidian, Mordru, and Eclipso.
Star Spangled Kid's prophecy is about the confrontation with the Jokerfied Solomon Grundy of "Last Laugh". The Atom (of all people) is predicting Infinite Crisis; interesting.
But Mr. Terrific and the Spectre? I'm not sure what they're predicting... .
I have a feeling if I read all of DC's comics over the last few years, I'd find quite a lot of hints and foreshadowings, since they've been planning this whole IC thing for a while.
Anyone else remember other hints?