I don't see it being impossible, yet will be difficult adding it to ffxiv's lore in a way. Unless garlemeld(misspell......I think) create a device that goes through dimension, time and space, bringing them to eorza while in battle w/ adam and eve. Then asking the WoL to help them bring back to their world before adam/eve not only trying to cause chaos, but to prevent the virus to spread. That's what came to mind.