Will I get a Visa?

There is going to be a lot of work you will need to do before getting back in the US, if at all. It's not going to be easy to return after this.

What do i have to do to change my b1 b2 visa for a f1 student visa here in ny to enroll in nyu ?

Yes, you cannot go to school on B1/B2. You will need to contact NYU and their CSO in order to determine their requirements for the F-1 visa...

Completed 5.8 yrs on L1B n H1B together, H1B visa expiry 12/30/17,approved I140. Can I change employer just with H1B transfer?

This is rather complicated, contact your company's attorney. They will have the most information and are in the best position to answer this...

Do I need to file Form I-693 with my adjustment of status application if I have been legally in the USA for years?

Yes, they are only useful if they are recent.

You should always be honest on the forms. So you will have to answer that she is out of status, or overstayed. Once you are a citizen you can...

What papers should I fill out?

Is your spouse a citizen or a green card holder? You can only adjust status if you are married to a US citizen. Otherwise you will have to have...

No, she cannot. She may be able to adopt the child and then get the green card but this is a lengthy process.

What suppose to be in my letter to immigration office to assist me to motivate my wife to go back with me to Nigeria?

Not sure exactly what your current visa status is, so it's difficult to say what your rights are. However, the US government will generally not...

Can I file N 400 while my I 751 in process?

Generally, it is advisable to file for citizenship as soon as you are eligible.

Just describe your business. Say you are self employed.