It preserves residency, not your eligibility towards citizenship.

Yes the divorce will likely impact the eligibility, especially with the arrest in last 5 years.

He may apply for a visa depending on his eligibility for the visa.

Best to consult with attorney who filed the U visa on your behalf.

You case is with the immigration court most likely given previous history. Consult with an attorney for guidance.

You should bring proof of extension filing through receipt notice.

Depends on the nature of your case. Consult with an attorney for guidance.

Yes a separate I864 form is required for each applicant.

Yes indicate your middle name on form I751.

Normally 30-90 days for re-review of documents.