Welcome to the site. I'm sorry you are going through all of this. I know it isn't easy. My son wasn't diagnosed until he was 15 yo. CF isn't something you want him to have, but once we had a name for what was causing Jordan's problems, it was easier to deal with. You can read our story in the Diagnosis section for the details.
I say do whatever you have to do to get the answers you need. I don't know anything about those hospitals/clinics, but it sounds like you've been given some good choices. Good luck, and please let us know what you find out.
Stacey