Yes.
Nope.
You can send it via email. Scan the data page of your new passport, and if your old passport has a stamp saying it has been cancelled, then scan that too. Then include a cover letter with your name, CEC file number, UCI, date of birth, and a short explanation to say that you have renewed your passport because it was close to expiring. Remember to date and sign the letter, and the entire scanned file should be less than 5MB. No need to fill forms again. It will cause confusion. I think that it's better to send this info as soon as you have it. Waiting till CIC requests it, may add a small delay.