g-28 form questions - post again

after I left my previous job, I want to terminate my lawyer by filing G-28 form. Here are questions that I have

1. do i need to fill my spouse's name and check Petitioner, Beneficiary, and Applicant?

2. for myself, should i check Petitioner, Applicant?

3. how can i prevent other lawyers in the same lawy firm accessing my case? my i-485 was filed by persaon B Esq. in addition to B, should I also mention the law firm?

4. Do i need to list my A#? (concern is how the USCIS find my case? i don't see ssn or other id other than my name and address in the form)

Thanks.