You know, it's funny; there was another superhuman RP on the Sporum that I joined a few years back in which I used characters also with the last name Park. Maybe it was a subconscious decision or something.
I tend to recycle last names a lot when it comes to my OCs, but for me it's mostly because I don't want to have to think of another last name ;v; I have this weird problem where I don't like using the same first or middle names for any of my OCs. This obsession has birthed some of the strangest names for my "children" like you wouldn't believe.
Also I just wanted to include that I loved the statement you used in Ratchet's character sheet about her focusing on the task at hand. Puns are my life juice.