>>32157992Manga means nothing. The Mangaka chooses the starter based on a triangle: one MC gets Grass starter, the next one gets Fire starter, then the next one gets the Water starter, then repeats again in Grass starter, etc.
See: Red and Bulbasaur, Gold and Cyndaquil, Brendan/Ruby and Mudkip, Diamond/Lucas and Turtwig, Black/Hilbert and Tepig, Blake/Nate and Oshawott, X/Calem and Chespin, or Sun and Litten.