OldUser

This depends on where sponsor lives, what's their household size, how many dependants they have and whether they sponsored anybody else who is still a green card holder. Details here: https://www.uscis.gov/i-864p

Sure, it should be sufficient. 3 years of marital evidence is good.

I'd provide some of those, at least new evidence.

Can get SS card in maiden name before marriage and then update it to married name in the future. Before chaging name, make sure to check how easy it is to change documents like passport in the country of origin. If name change there is too difficult or impossible, then consider whether the name change is the right move at all. Having name Anna Smith in home country and Anna Brown in the USA is possible, but not ideal for travel, legal and other purposes. It's nice to have consistent name documented in different jurisdictions.

Not needed Who's? Applicant's not needed. US citizen spouse's? Not needed Not needed Good Hopefully I-751, there is no 1-751 Bank statements, utilities, some other proof of joint marital stuff?

There is no co-sponsors. Petitioner will always be the main sponsor, but can have joint sponsor. Joint sponsor should have enough income alone to support immigrant. You can't add main and joint sponsor's income to qualify.

I wasn't asked about my employment at all at N-400 interview... I can give you 90% chance the max you will be asked is your current employment status. Here's how I would answer the same set of questions personally: And where do you work? (place) I’m self-employed. Where have you worked for the last five years? I've been self-employed all this time What other places have you worked at in the last five years? I haven't worked at any other places How long have you worked there? I’ve been self-employed since 2010.

Joint

This would be my recommendation too, as long as GC holder stays in the US for real, and don't just visit for few weeks.

There is no set time for AP

You would say they are not members of the same household because they file taxes separately.

I would think you'd shoot yourself in a leg applying for visa while you are unemployed. I'd recommend getting a job in Canada before attempting B1/B2. Job is a tie to a country of your residence.

K-1 is not a try "before you buy" type of visa. It is for somebody who knows why they want to marry their significant one. K-1 petitioner promises the US government to marry the foreigner.

Household member is not about living at same physical place. Household member is when you combine incomes for tax purposes. Unless your wife or her father claim each other as dependants on taxes, they are not part of same household. So most likely father will be a joint sponsor, unless they are members of same household.

All applicants is everybody, including VAWA, General Provision, Marriage based, Military provision etc. It says there is required evidence for all applicants when it comes to marital status. Just like all applicants (including VAWA) must submit front and back of their GC with N-400. I'm not talking about evidence of bonafide marriage etc. Simply doc that proves marital status. Married - marriage certificate Divorced - divorce certificate. I applied under general provision. I got GC through spouse, and still married to same spouse. I provided same marriage certificate for I-485 and N-400. The naturalization certificate shows marital status at time of naturalization. N-400 form asks for marital status even if filing under VAWA. The certificate (marriage or divorce) is proof of marital status.

What if person was married before and now divorced? It's not required to be married or divorced to file for N-400 under VAWA but it is required to provide evidence of current marital status. Instructions clearly say: All applicants must provide (if applicable) LPR Card (Green Card): A copy of your Permanent Resident Card (also known as a Green Card) (both sides) Form N-648, Medical Certification for Disability Exceptions: If you have a physical or developmental disability or mental impairment that prevents you from complying with the English language and/or civics requirements for naturalization, submit a completed Form N-648 to request an exception to the English language and/or civics tests. Marital Status: Provide current marriage certificate and any divorce decree, annulment decree, or death certificate showing that your prior marriages were terminated (if applicable). Source: https://www.uscis.gov/n-400 Where? N-400 is a standalone application and requires its own evidence. Including evidence of current (not past) marital status even if it has not changed in decades.

What do you mean by that? You absolutely need marriage or divorce certificate to document current marital status on N-400, whether you file under VAWA or not?

The very first I-797 typically extends the validity of green card. Read here https://www.uscis.gov/newsroom/alerts/uscis-extends-green-card-validity-extension-to-36-months-for-green-card-renewals

How long has he been living in Tijuana for? When you mean renewal, do you mean I-90 to renew his 10 year green card? After I-90 is filed, applicant receives extension letter.

Not really. The visas are limited by law.

My understanding, it should not be a problem, but there are new Good Moral Character rules and I don't have enough info on those. Payment plan should be acceptable, it's usually failure to file or pay taxes that can cause issues. Others can comment.

OP was denied reentry permit, I don't see how SB-1 would be approved. OP has close to no ties to the US to the point they were given ESTA. I hope correct info was put in ESTA application, I'm sure it asks whether anybody ever sponsored them for visa etc.

Right, another reason to start from scratch. OP, make sure both parents petition you. Considering long wait, this helps if one of the parents passes away meanwhile. Hopefully both parents are alive and healthy by the time you will be processed, but you never know