>>53869992I think the modern setting was a thing since the earliest concept. The setting was based on Ultra shows, which is also the origin of the Capsule Monster concept. And considering that the initial idea had you selling capumon to stores and buying them from gachapon machines, a modern setting was very much necessary.
I think the biggest influence MOTHER had on Pokémon was the Psychic type and Mewtwo, who shares some similarities with Giegue.