Would it cause delay due to name changed after marriage on documents? Or any kind of trouble?

This is a normal practice. There would be no issue.

Catholic marriage but separated

Do you mean divorce by seperation? US recognize legal documents from other countries.

Spouse's change of status from F2 to F1, when my H1B is under processing

Change of status is from F2 to F1. However, she cannot start study before receiving official approval.

Selected as the best answer

How can i go on F1 visa while i am already in the United States?

Did you have any attorney for your U visa? If not, you need one now.

Can someone get DACA even though they have an order of deportation on them?

Yes, your daughter can get DACA even if she is in removal proceeding.

How quickly or fast can a H1B petition revoked?

Do you mean revoking the petition or withdrawing the petition? revoking is by USCIS while withdrawing is by your employer.

If I receive the Receipt number from USCIS about H1B visa application, does it mean that I was picked through the lottery?

Yes, you were one of the lucky ones. Congrats.

What else do l need (2) ?

You do not need to convince the officer that you are not mentally ill. As long as you answer truthfully the questions on your I-160 or other form...

Is there a visa that would allow me to work in the US temporarily without needing an American sponsor?

J visa may be an option for you if you like to work over the summer or so.

I-751 Filed in vermont Service Center and still waiting for decision.

Check with USCIS. Sometimes it happens. You need to obtain a stamp if you want to go to Canada.