1. Yes.
2. They made me cut the PR card in 4 pieces on camera.
3. I sent them the Affirmation of Oath form and they mailed the citizenship certificate. Since mine was Urgent Processing application, citizenship application was also expedited. I received my citizenship certificate yesterday.
4. Not sure but you can check with the clerk at the ceremony and ask them if they'll mail the certificate to a US address.
I have made a detailed post about my Virtual oath ceremony experience, in case you are interested =>
https://www.canadavisa.com/canada-immigration-discussion-board/threads/virtual-citizenship-ceremony-experience-raj.742497/