You each file your own petition separately.
Yes.
Choose the one that's convenient for you.
When you bring your petitions to the courthouse you'll be assigned a case number. Bring duplicates of your petition so you can put your case number on it and have your own copy date stamped by the clerk.
Make sure you carefully read and follow all of the instructions on Page 2:
http://www.courts.ca.gov/documents/nc100.pdf

