It's not a problem, you can use it if and when it is approved.

In the very unlikely event that you get a waiver for the two year home residency, yes, you can adjust.

You need to show ties to your home country, sufficient income for your trip, proof you intend to return to your country, and rehabilitation from...

Yes, you can use a relative's address as your mailing address.

If you are working outside of the U.S., it will not violate your H4 status.

It means the I-140 priority date, not the I-485 date.

You can schedule with the U.S. embassy or consulate to apply for issuance of an F1 visa.

You are allowed to work abroad if you have an H1b. There is no need for an LCA for work you are doing abroad.

The form is number N-648 Medical Exemption.

From your description it appears you spent less than 180 days of unlawful presence, so there is no bar to admission to the U.S. based on unlawful...