This will not impact your citizenship and the I130 cannot be withdrawn by anyone but you.

The I485 approval and physical GC shortly after.

Likely not given length of time that has lapsed but confirm with USCIS.

No this is not possible given facts of your case.

No you must have met prior to filing.

This is not an immigration related question but most likely, yes.

You should consult with an attorney to review the prospects of your case.

This can be corrected at time of interview.

Your mother may apply for a visitor visa with a showing of sufficient family and financial ties to her home country.

Your case will go to National Benefits Center first and then the local service center. Processing should be between 12-18 months.