F1 VISAS expires and looking for solution

I agree with Ruby who covered all aspects of your question.

Should I been concerned if I haven't received a confirmation letter in the mail?

You will not receive a confirmation about filing an AR-11. Just keep a print out of the online filing confirmation.

How to get proof of my admission to the US when I lost my passport and I-94

If your passport was stamped when you last entered, you may submit a copy of the entry stamp as proof of lawful admission. Otherwise, you need to...

Travelling with ESTA, then initiate L2 process

Your wife can enter under ESTA program but has to leave within 90 days. She can apply for an L-2 visa at a later point in time.

My H1B stamp on my passport is still valid although I already moved back to my home country. Question is: can I use H1B visa for

The visa would be only good for coming back to the US to resume employment under an approved H-1B petition. You would have to apply for a visitor...

I751

I agree with my colleagues.

Your free to leave at any time.

Change of employer and have valid H1B visa , Do I need to go for re-stamping?

You can re-enter the US using the H-1B visa that was issued based on petition from prior employer as long as it is still valid. You must present...

Is it better to take lawyer to the second AOS interview through marriage?

I recommend hiring an attorney to prepare you for and represent you at the interview. It is particularly important to have someone on your side who...

How does dcse get an illigal alien to pay child support?

You should consult with a family law attorney.