Upon another reading of the full material here, I've changed my stance. Looking over these, it 100 percent looked like a willpower feat. Pariah did use Crisis energy to create universes for each of them, linked directly to each of their minds. While they were in these worlds, he was using the power of the Justice League to replace he multiverse with a recreated Infinite Earths multiverse that wasnt quite finalized yet. Their power not only gave him the energy to do it, but also were the stabilizing force of the new multiverse. I can only imagine that this was a bit of a modern throwback to AntiMonitor using the heros energy in COIE, but a bit more complex.
What Superman did, was absorb those universes worth of Crisis energy[at minimum his own, but they were standing on a blank canvas], and then free the league, and that made Pariah fall short on energy and he went pleading for more power.
So, what he really did was absorb a universe[s] of cosmic power/creation energy.