We just filed DCF in Italy a few months ago and I was also confused with the I-864 and domicile. For your specific questions, this is what we did:
Part 2 (Address of Principal Immigrant) - Your UK husband is the principal immigrant so you want to put his current UK address
Section 4 - For both mailing address and residence address I used my overseas address as per DCF you have to have residence in that country. Then for country of domicile I used US. Not sure if this was the correct way to do it but I did not have problems.
Part 6 - This was the one I had concerns with the most. I put that I was currently employed at the Italian place of work. However 13.a.1 etc, I put 0. I was asked about it at the document checking stage of the interview and said that I was currently employed however, that job would not be following me to the US and it was not US based. The lady was okay with that and honestly did not look at the rest.
From what I saw as you will not be able to solely support your husband and that you will have no income, they mark your I-864 as DOES NOT MEET requirements and focuses mainly on the co-sponsor. Like I said, I am not 100% that I filled out the form correctly but we were issued a visa in the end so it couldn't have been too bad.
For proof of domicile, I had the following: (I have been living in Italy and Spain for the past 6 years and am also moving back without a job in place)
Tax Exemption Letter (I did not file US taxes for these 6 years as I did not make the required amount to do so), Letter on steps I took to reestablish domicile, Letter from my parents stating an agreement to live at their house, Email from our local insurance company stating options for health insurance, Email from pet relocation agency, Bank statement, copy of drivers license.
For cosponsors, make sure you have their W-2 in addition to the tax return if they file jointly as we were specifically asked for it as the tax return then would show a total of both your parents income where the W-2 shows only the co-sponsors income.
Je e Gi got a reaction from Darnell in Filling in I-864 - Sponsor is immigrating back to the US with the beneficiary (no job as of yet)