Hear me out guys...I have a hypothesis on what this new Pokemon will be, and how it may relate to Gen 8.
For starters, let's look at some clues we have so far this gen. On Route 8 in Alola, there was that fossil guy who wanted to have a Jurassic-like theme park. Some new dex entries talk about how Pokemon used to be or possibly look (Tyrantrum possibly having feathers, Wailmer walked on land). There's even mention of a live specimen of a Kabuto that never went extinct, meaning no rock type.
Then, we've seen Masuda and them have been looking at old cave paintings in Europe in the last couple of years.
All of this seems to be pointing to some sort of ancient time period for our next region possibly. Or it could involve time travel...which would fit snugly in with possible Sinnoh remakes.
To top it all off, this new Pokemon, we assume #808 in the national dex, will in fact be indexed as #000, so it doesn't mess with the Kanto dex and won't cause any trouble when sent to Go (otherwise it would look tacky if it was truly #808 when we're not even at Gen 4, and it can't be 152 without fucking up the national dex). And I believe It will be the first descendant of Mew, as all Pokemon carry Mew's DNA to some extent. But who or what was technically the very first?
This would tie into the gathered clues very nicely. All about ancient Pokemon, something to do with actual time.
