After how many months of arriving in the U.S on a B1/B2 visa and then marrying with a U.S citizen, would be considered safe?

The issue is not how many months you wait to apply but whether you had a preconceived intent to get married when you arrived in the United States...

How is the 30 day period for filing an appeal figured based on a real calendar?

Because the 30th day was a Sunday.

What are my chances of becoming a resident of some sort and joining the marines?

You should apply for deferred action if you have a clean criminal record.

What is Passport validity rule for extension of tourist visa. Want to extend b1/b2 by 6 months but passport is expiring 5 months

In the worst case they will extend her visa until the date her passport expires.

Can I work under a F2 visa? If yes, are there any restrictions in terms of payment or time? If no, can the visa be changed?

You cannot legally work on an F2 but can change your status to a nonimmigrant working visa if you find an employer to sponsor you

I have two friends who were married in Mexico, they have 2 kids and another on the way...they are here in the USA.

US citizen children must be 21 to sponsor their parents

F my H1-B gets rejected, Can I still apply for my OPT extension under STEM?

Apply fgor OPT extension as soon as possible.

Applied for the DV-lottery while still in my country and got the news about winning it while am an illegal immigrant.

Are you saying you are in the US. If so, how did you enter? How long have you been here unlawfully? You need to discuss your case with an...

You will not lose your citizenship unless the USCIS for some reason proves that your green card was obtained fraudulently

I want to apply for the deferred action, I have never committed a crime, do i have to get my criminal record?

You do not need to get police records. You do need proof that oyu have lived here 5 years and satisfy the other requirements such as graduated...