Cool! The Gym-leader here in Olivine focuses on steel types, so it's funny you'd choose that.

As for soul resonance... Well, I wouldn't really say it's common, but there's enough people who can do it that a school has been set up to teach regular humans how to control it and stuff. Witches are capable of doing it as well- maybe other creatures but I don't know anything about that.

Well- the DWMA teaches both about how to deal with our souls, and how Demon Weapons, people who can transform into weapons, how to deal with their abilities.

I can tell you more about it if you want.