Amend an existing F1 to H4 COS application ?

These are questions you need to address with your attorney, he would be able to advise you best since he knows your case. Visit to local USIS will...

My GC approved recently. The week prior to approval, I had sent in my EAD renewal to NSC. Should I withdraw or let them deny?

Withdraw with a cover letter explaining your permanent residence was approved.

Can i use a cpoy of greencard to go back to usa?

You can apply for a travel document, https://www.uscis.gov/i-131a.

I applied for COS from H4 to F1 and got it approved. Is it advisable to go to Canada for F1 stamping?I am on OPT STEM Ext now.

You don't have to travel now to obtain your F1 visa stamp if your change of status is approved. If you are wanting to travel internationally and...

Disclose the Master's degree if the question requires the information, it will not affect the H1B or the approved PERM or I-140.

RFE on h1b amendment of role change

If the amendment is denied, you will need to work in the H1B position that was approved.

Fake Tax Declaration.

Talk to a family law attorney about this, not immigration lawyers. You seem to be making assumptions without evidence, so doubtful USCIS will...

Temporary Green Card, Naturalization and Divorce?

Yes filing for divorce will impact the naturalization as they will question if the marriage was entered into good faith, and yes he will have to...

Lying under Oath in the Declaration. Is it any legal penalties for that?

You do not address why this is any of your business. You can always contact ICE with information if you think its relevant but to put the...

Do I have to list an MIP in visa application?

Disclose the information on your visa application with a formal disposition of the incident, it should not get in the way of visa issuance.