I try not to ignore any of the in-game/side story lore, as I'd always found it more enriching to ground my own ideas and works in as much of the lore as possible. But I'm not perfect. Invariably some of my ideas will go against the grain—such as, for instance, Gaia being able to effortlessly create void portals where everyone else struggles to do so.

That said, I hate moments in the story where the heroes become uncharacteristically stupid or passive. I usually try to imagine workaround scenarios for those, wherein something is discussed/done, but ultimately the same outcome transpires. I don't usually make exceptions on the latter half of that, though I am very partial to the "Ahewan didn't die" stuff I've seen on Twitter.

Oh, and I made two gigantic exceptions at the end of my last fic, Amidst the Ashes of Paradise. Even then, it's not so much that I ignored the lore as it is I've decided to ignore it going forward from there. The first is that the rest of the story going forward is Minfilia's, not the WoL's, and that she's alive again. The second is that the WoL pieced Venat's soul back together, allowing her to reenter the cycle of life, death, and rebirth.

I'll probably throw in a third exception, retroactively, if 5.4's Pandaemonium stuff keeps trying to throw in Chrono Trigger rules into FFXIV's already needlessly convoluted time travel.