Immigration Site

I am a US citizen recently married to my husband from Argentina. I am 4 months pregnant and we have filed our I-130 and now waiting. I plan to stay with my husband as long as possible here in Argentina. Hopefully this is through the interview and we can fly to the USA together. Below are my questions regarding what to do next, our sponsor and the I-864.
Does the NVC mail a packet to my husbands address here in Argentina with instructions? I planned to fill out all papework by downloading and printing form my computer.
Once we complete all forms what do we do?
Will they be sending us an alien registration number to include in the next set of forms?
Since I am currently outside the united states and need to prove my domicile in the United States I will have to use my mailing address . I have been living abroad the past 4 years, but I have maintained my Parent’s address in Oregon as my permanent address. How to do I prove this. Do I have my mom fax copies of mail sent to me?
What can I do for concret proof that we plan to be domiciled In the United States? This is difficult because I am not in the United States. I can have my parents draw up a contract or rental agreement, (they have a couple rental properties) but we are planning to stay with them for a couple weeks, while we find a place to live. I am also going to be contacting Doctors with questions for finding a Hospital and Delivery plan. Can I attatch these conversations as proof? We can’t really do much, until we move there.
I have no income and tax information for the past 3 years because I was living abroad and didn’t’ make any income to file. We have a sponsor, but I am still nervous about not filing my taxes or having a bank account. Will a written explanation of why I did not flie, alone be enough evidence.
When should we have our sponsor fill and complete the I-864? Do we have him send his paperwork to us in Argentina?
I have asked this question again, but let’s say our papers I-130 arrived today at the USCIS office. How long do you think the entire process might take. I’m trying to look for tickets to estimate our travel expenses. I know it’s only an estimate!

Thanks so much