Your question is unclear - why is interview scheduled if case denied?

Contact NVC to have her added to your case.

Yes she may apply for a tourist visa if eligible.

No best to have this resolved before proceeding.

This should not be your intent upon entry - to later change status.

Every four months is ok, first page no advertisements and yes you can include main lease and signature pages.

Yes if the proceedings were terminated in court you may file for AOS.

You appear eligible to petition as sponsor. Refer to the I864P for guidance.

You must provide information re: 2018 and 2019 and are required to provide documentation for 2020.

He should not withhold your documents due to unpaid balance but best to communicate directly with him for assistance.