Would it be wise for him to apply for a visitor's visa before we get married or after or any at all?

You would only be required to make above the poverty guidelines or have a joint sponsor, its around 19K for 2 people. Also you should not have him...

L2 to L1 visa conversion

You should refer these questions to the attorney assisting your company with the process.

I recently got my Permanent Resident card last Dec. 19,2013. Been married to my US Citizen husband for 11 years.

4 years and 9 months from the date on your green card. Unfortunately, because of your husband dieing, you do not get the married to a citizen speed...

I believe as long as you do not plan on traveling in the time period it takes to get approved, you do not need to renew your green card.

I'm in H4 and just traveled out of US for vacation until july.My H1B got selected in lottery today.

This will not affect your potential for approval, however, If you leave the United States before your change of status is approved by USCIS, you...

Selected as the best answer

I just got my I-130 approved, and I left USA on April of 2013 with a order of voluntary deportation;

Waivers can be very difficult to write, I strongly suggest you hire an experienced attorney to assist you in the process.

(Petitioner or Beneficiary) Self petition Adjustment of status

I believe applicant is correct. I wonder if anyone ever even reads the cover letters.

I-130 Process time

https://egov.uscis.gov/cris/processingTimesDisplay.do

I already gave you the answer. GENERAL QUALIFICATIONS* U.S. citizen or permanent resident alien

There could be immigration consequences if you leave the country, you should discuss this with your immigration attorney directly.