I can care less what ppl bring, even the Lapras, Rhyhorn blah blah was drawn first from the creator. Arceus was the first pokemon in existence story wise. Even if he was introduced way later in gen 4.

Humans discovered bulbasaur first so it's why it's the first in the Pokedex. Mew is the Ancestor of pokemon, but Gods overank those. Nothing else in the pokemon could be alive because of Arceus, he made the pokemon world and the universe itself, that to me is enough to convince. Til I see those entries on Mew, Rhyhorn, Lapras, or w/e. Arceus is first in the world.