If you are subject to Fair Housing, then you should print, read, highlight, and learn the policy regarding service animals: https://www.hud.gov/sites/dfiles/PA/documents/HUDAsstAnimalN...3.

I have the court documents if you need them for reference.

So, everything the law required of me in such a case at that time I did - and each required step I took, I documented by email to the tenant, with attachments, where appropriate, without delay.

Documentation must be provided to prove the change in occupancy status​.Non-Occupant Co-Borrowers: A borrower who is a non-occupant co-borrower on another FHA loan may still be eligible for an FHA loan on a property they intend to occupy as their primary residence​.If you want to rent out your current home and you need the rent to offset your current mortgage payment to qualify for the new loan, you run into another set of FHA rules. 

If possible I'd even request it be documented on the invoice.

A Borrower with an existing FHA-insured Mortgage on their own Principal Residence may qualify as a non-occupying co-Borrower on other FHA-insured Mortgages.Rental Income from other real estate holdings may be considered Effective Income if the documentation requirements listed below are met.

Make sure to have clear documentation of regular, on time rent payments and the agreement clearly laid out.

The City of San Jose has on their website that new addresses are required but separate meters are optional (link below).https://snapadu.com/blog/electric-panels-upgrades-power-sources-adu/https://cao-94612.s3.amazonaws.com/documents/City-of-Oakland.PGE-Joint-Information-Bulletin-METERS-FINAL.pdfhttps://www.sanjoseca.gov/business/development-services-permit-center/accessory-dwelling-units-adus/adu-faqs

They should have the policy documents from many of the new home loans they have done.

Once you have that letter you can use an LLC formation document template to create the LLC and register it with the corporations division of your state or jurisdiction.