Maybe Mew is somewhat like Adam AND Eve as one person(pokemon) and Arceus Plays the role of God (the creator) thoughts?
That would require lesser Pokemon to be alreadybe in existance in this metaphorical "Garden of Mewden" prior to the pink furball's creation and Mew would therefore not have any genetic connection to any of them.
Has anyone really been far even as decided to use even go want to do look more like?