[@The One] The First Great War happened centuries before PMD R/BRT. So that's something that no one would remember except through the few legends scattered throughout various ruins, or by the Legendary Pokemon themselves.

As for the Guild, you didn't give much information about it that I can really make a decision on. Where's it located, what does it do, what are any current members of it? If it was formed after the Second Great War, then it's been about Ten Years since it was formed.

Also, I've never really understood the whole thing with the Shaymin Village being cut off from civilization since, after being exposed to Gracedia Pollen, they can fly and go for help. Not something wrong, just something Lore-Wise I've never understood.