When H4 EAD renewal will be adjudicated?

That is very unusual. Consult with the company attorney for resolution ideas.

Changing statues from L1 to L2

There are complicated practical and legal considerations involved in determining when these types of applications should be filed. Consult with an...

No online status update after AoS interview. It has been more than 1 month now.

You can schedule an InfoPass appointment after 60 days have passed since the interview.

How long do you have to hold a green card in order to join the U.S military

There is no requirement. Consult with the local recruiting office of the branch she is considering joining.

There is no "correct" number of documents to be submitted, however, the more probative evidence submitted with the filing, the better.

Can one transfer and extend an H1B to a new employer based on approved I140 of current employer ?

You can extend H-1B status beyond 6 years based on an I-140 filed by a different employer.

What kind of benefits a international student get if giving a child birth in usa?

No, parents cannot stay in the US based solely on having a US-born child.

Can my non immigrant status (F1) will remain same if I will not approved from NIW i-40 immigrant petition?

Your F-1 status requires that you remain a bona fide non-immigrant.

If I am missing a single letter in my given name in greencard, is it going to be a problem while entering into USA?

No, this should not be a major problem, however, you should file fro a replacement green card to correct the error.

Does my spouse have to include visa records issued before our marriage? She is filing I-485 as a derivative applicant.

She should provide evidence of lawful admission to the US, as indicated in the instructions for I-485.