I don't think so, I think the only similarities they have is that they are blonde short girls that love Pokemon. I don't think they are related because those are pretty common traits that can be share between people who aren't related.
I don't think they're counterparts either. Yellow is more of a typical cleric character as she's shy, caring, and she doesn't really like to fight unless they have to. She even has the ability to heal. While Bonnie is more so an excitable and curious child.