Kimdung92

The mortgage piece has nothing to do with the filing.
 
It's hard to say what is "best" in your case without knowing all the numbers of everybody involved.
 
Your husband must file an I-864 (or I-864EZ if he qualifies).
Your husband's stepfather can file either an I-864 or I-864A. Generally, the I-864A route would be better since it lets your husband combine his income with his stepfather and there's no children involved to make the household counts considerably different vs him filing his own I-864.
Both your husband and his stepfather would provide evidence of their income, and at least the most recent year's tax return.
 
I highly suggest re-reading the I-864 and I-864A instructions until you (and your spouse) are confident that you understand them and how they apply to your specific situation.

I think we probably all agree it's a good idea to know your future spouse before marriage. Choosing to AOS from a K1 or choosing to come over on a CR1/IR1 does not in any way impede that. Many people visit successfully on tourist visas before and during the processing of those visas. Or the future spouse visits you in your home country. 
 
Anyway, this is really besides the point as the OP has gotten the answer to the question originally asked. I wish the OP good luck with AOSing.

Orangesapples,  i am just trying to put across a message. We cannot continue to judge people  on INTENT.  People are  already going through lot of stress . 

The idea that people with B1/B2 or ESTA have intent to stay is inaccurate. I came here on B2 with a plan of staying for 3month. However, you will all agree with me, coming from a different country with different cultures, it would take time to overcome the issues highlighted.
Even after our 5month staying together, we were still having issues. It was only after my 7months I felt comfortable to ask her to marry me.  As I write this piece, I can honestly say that my wife and I understand each other very well. She knows what offends me and I also know what offends her.
We have to know ours spouses before making that supreme sacrifice to stay here.  I am now trapped in the US, no JOB and I can't see my Son for close to 1 year.  I was making close to $6k per month in my country.
I knew of CR1 Visa before coming (Please note I visited the US twice before staying), However, I was really more concern in knowing my wife before marrying here.
Finally, I have seen people who came here with K1 visa, guest what, 4 months after marriage, everything collapsed. My neighbour came with CR1, he and the wife knew each other for more than 3 years but the maximum time they spent together was 2months. In less than a year they divorce. These are all caused by marrying someone who you don’t know very well.
Cognizant of these, AOS is open to all who enter the US legally. Trust me if USCIS was looking for intent, none of us would be permanent resident.
 
florida racer 73 Please work on your relationship and gather evidence to support your marriage.

I-864 is the main form. I-864EZ is a simplified form that can be used for the most common circumstances. The requirements to use it are at the very beginning of the I-864EZ (i.e. a joint sponsor cannot use it).
If you use an I-864EZ, then this replaces the need for the I-864.
 
I-864A is for relative living withing in the same residence as a sponsor. This is a an agreement to combine their income/assets with the sponsor (the sponsor is somebody using the I-864/I-864EZ).
 
Roger. No I-864A is needed from her then.

Yes. He would provide a letter stating why he did not need to file for the other 2 years (i.e. having no income).
The joint sponsor (father) needs to file an I-864.
If the father files taxes jointly with a spouse, then the spouse should file an I-864A as well.

It is a relatively straightforward process, read the guides carefully, not quick, not cheap but doable if you pay attention.

I was wondering when the AOS police would show up... 
 
OP, you'll be fine, just don't leave the US without an AP and start collecting as much evidence as possible. At my interview, the officer really liked all the financial documents we presented. 

Okay, good luck to you!

I m not illegal, because I got the proposal when I got here and it was a spontaneous wedding ☺️

Why be separated again for a year or more when they are now together? 

Haha they will staple them again anyways. They rejected one of my packages before and it came back stapled. 

Use this guide:  http://www.visajourney.com/content/i130guide2

Your husband is the primary sponsor.  He must complete an I-864.

Yes, co-sponsors must also file financial responsibility paperwork. I am not an expert on co-sponsors, so I defer to others for their expert advice on this subject.

The petitioner must file an I-864 and provide the most recent tax return (and have filed st least the last 3 years of tax returns).
 
A joint sponsor must do the same (including evidence of their income/assets used, such as pay stubs or an employment letter). If the joint sponsor files jointly with a spouse, then the spouse should file an I-864A and provide documentation as well.

My (now ex) husband couldn't show any tax return so he included a letter as to why he didn't have one. He didn't have a job and we used his uncle as a co-sponsor.