USC applying for child?

If your child was born in the US. then your child is a US citizen. If your child was not born in the US, then the child would only be a US citizen...

Can i file EAD (L2 visa) from home country or is it mandatory to be in the US?

You need to have an EAD in order to work.

How do i organize my document for a green card based on marriage interview? how do i prepare myself?

It depends on how much older. Two-three years would not be a problem. Twenty-thirty years would create an issue.

Will positive shyphlies deny my immigration case?

Your question is unclear. Who has syphilis? if you have it and are a US citizen, it is completely irrelevant to the immigration case. If your...

Is permanant resident married to usa citizen ..can apply for citizen after 3 yrs of marriage even they are not married now.

No. If the marriage is over, she needs to wait until she qualifies under the five year rule. And your question appears to suggest that she does.

Where to send the I-140 portability letter?

The office where the I-485 is pending based on the receipt.

How much do I have to wait to change my B2 status to permanent residence?

There are not enough facts here. If your spouse is still an LPR, then yes, you have to wait one year. If your spouse is now a US citizen, then...

How am I able to obtain a State ID?

They are probably looking for evidence of valid immigration status, e.g. US Citizenship or a Green Card.

No. You cannot. The H-1B allows employment only with the employer who filed the petition. For the restaurant, you would have to change your status...

Will I be allowed to re-enter the US after 6-day out of status in the US

It is almost certain that, if USCIS approves the petition, it will approve only the petition and not the extension of status. That means that you...