Brian, what you have are two "Gaijin" cards. Gaijin is a term used for non-Japanese players in the Japanese League. It literally means "foreigner". Since the first guy is American and the second guy has been identified as Korean they would both fall under this category.
As far as identifying the American, I can't help you. But I know a guy who can. His name is Rob. You'll find his contact info on his website:
http://www.robsjapanesecards.com/
Congrats on your additions, perhaps you're unintentionally (or intentionally) becoming the next big collector of Japanese menko cards! There's not too many out there!