L2EAD stay and work status extension?

No, you cannot stay in the US if your spouse's employment is terminated. Your L-2 status and ability to work with an EAD is a "dependent" benefit...

Our nvc papers have been completed & Approved..how long until we receive a interview date. My wife is in the Philippines.

The interview wait time is different in each individual case. It will be probably a few months.

Applying for citizenship before I get my second green card?

Yes, you can file your Application for Naturalization as soon as you are eligible, i.e. 90 days before you reach 3 years since you received your...

What is the best option to select in N-400--5 years of permanent residence or 3 years of residence as US citizen's spouse?

You can use either option. Provided you are still married to and living with the same spouse through whom you obtained your green card, you can use...

Immigration/i-864/immediate relative/ What is the size of my household that needs to be declared in each I-864?

I agree with the above answer. The household size is three (3) people.

Is it better to seek extension of L1B status within US or country of Origin.

Speak with the attorney who handles your case. In general, one needs to apply for extensions of status in the US. The visa validity is not material...

I-485 Re-submission - Receipt Notice?

Be patient. The receipt will come. I expect that the attorney requested the applications be adjudicated together.

What's the earliest my wife can file for citizenship (submit the N-400)?

She can file an application for naturalization three years after she first obtained her green card, provided you are still married and living...

Contact a CBP office, Secondary Inspection, in your city and see if they can fix it for you.

What happens to my current F2 visa, can I enter the US with it if my F1 visa gets rejected in US consulate?

You need to speak with an immigration attorney. The F-2 is a dependent visa. Your F-2 status terminated upon termination of your husband's F-1...