I've been thinking something similar. SE had deliberately kept Derplander as the generic WoL representative all this time - why suddenly introduce him and the rest of his crew as antagonists?

We saw them returned after the time skip in the opening movie to 2.0, and he was there at the start of 3.0 as well. What if the Ascians got a hold of them from the universe where they were the Warriors of Light, and flung them into this one to try to stop the future?

FFXI used this sort of storyline in Wings of the Goddess and in Abyssea.
The protagonist and the antagonist in WotG were the same girl from different universes - Lilsette from the universe where Shadow Lord was defeated, and Lady Lilith from the universe where Shadow Lord was victorious. It turns out that the first universe was a false future created by Altana's meddling via Cait Sith and Atomos - the Goddess did not want her creation destroyed and chose Lilsette and the player characters to go back in time to alter the past. Lady Lilith came to this timeline to stop us and protect her own future.

In Abyssea, your player character lost the final battle with Promathia at the end of CoP, an earlier expansion, and the Apocalypse happened in their universe. Joachim found a bridge between timelines/universes just like Lady Lillith, and recruited the player characters to stop the reign of Shinryu (who was formed when Promathia consumed the power of Phoenix/Sel'teus.)


And that's not even touching on FF8 and Time Compression.