mgnfails

I am applying for a UK Spousal Visa. I am in the USA and my partner is in the UK.

For the accommodation requirements I am wondering if the tenancy agreement is necessary. The house that he resides in he currently rents in a flat share and has lived there for 5 years. He never has had a tenancy agreement for the house. It is man's honor that rent will be paid with all the tenants in the house.

We are able to provide a letter from landlord with him stating we can live in the house indefinitely etc., and we can also provide a property inspection.

One room in the house share pays bills so know bills are in my partner's name.

My question is:

1)will the letter from landlord
2) proof he owns the property
3) Property inspection
Be enough for the accommodation requirement? Or is a tenancy agreement mandatory for the application?
Also, should I summit bill's of the house such as council tax under my flatmates name, or are they not necessary to provide?

Thank you for the help!