You need underlying eligibility for an EAD.

You will need a cosignor for this requirement.

The cosignor would need appropriate income for both sponsorships.

No that is not a basis for denial.

An application for adjustment of status with all forms and evidence. Consult with an attorney for guidance.

Yes but likely with a waiver. Consult with an attorney to discuss.

No this is not possible and new application must be filed.

She can file under the 5 year rule.

If eligible she may file for AOS but consult with an attorney to confirm.

No you may apply now but best to have an attorney review. Good luck!