Actually, it is proper to use "and" in this case. Here, "and" does not have the meaning "plus."
Think: "The richest of the following four brothers: Ted, Fred, Steve, and Bill."
However, I assert that the word "lesser" is wrong, and should be "least."
Regards,
You are probably correct now that I read it again, however I think the word “or” would have been a better choice.