Nonono, it doesn't matter if theres more of one kind, but It would be better. Way better if there would be AT LEAST one of each.
Theres no cap limit on how many people there can be of one element. However his history isn't good enough because his character apparently lived in a forest. Too bad all the forests are cut out...

For the ones who saw the movie Wall-e, it's like that. Trash everywhere, no plants. Except that here there still are people living in cities.