Personal letters describing unusual circumstances of employment may be sufficient. Include mailing address, phone number and email address.

In general, one properly and timely submission/response to RFE is sufficient. Duplicate or multiple submissions risk USCIS delay in processing.

I agree with all the above suggestions by lawyers. It is difficult to know the specific issue you have. You may contact and retain a lawyer for...

By regulation, the I-751 is the beneficiary's form does not the sponsor. If by "sponsor" you mean petitioner, technically, the petitioner cannot...

It is possible. Consult a lawyer for further guidance.

Consult with a lawyer for other options which you may qualify.

Eligibility in your case is 5 years, mom 3 years if certain requirements are met.

At this time no action is required from you. USCIS will remain in touch with you.

Your response to the RFE would be considered unsolicited and unacceptable. USCIS is expecting to hear from employer not you.

I agree with the above attorneys' assessment.