I recently moved from Greenbee to Plusnet so was in a similar situation to you.
In answer to your questions:
1. My BB changeover was seamless, got an email to say it had been done & just logged back in again using my new PN details.
2. I'm sure that's possible as I kept my Waitrose email address when I moved over ( I had previously kept it when I went from Waitrose to ...



