accomodation issue online form on spouse visa

[Zach93]

hiya, i was applying for extension of spouse visa using the online form and came across this part, where it requires me to check all 3 boxes to proceed but it states this,

You only need to provide this evidence if...
You are exempt from meeting the income threshold
You are responsible for some housing costs such as rent, mortgage or council tax

I will provide:
[] Proof of property ownership from the owner of the property you live in, such as a mortgage statement
[] Copy of an ID document of the owner of the property you live in, such as a passport
[] Letter signed by the owner of the property you live in stating that you have permission to live there

the issue being that me and my partner live with my mother in law in a rented accommodation. my question is whether i have to provide all three documents or not as i am not exempted from meeting the income threshold and i'm not responsible for housing cost.

also is it sufficient that i provide instead:
1) tenancy agreement which listed me and my partner as member of tenants who are non tenant
2) a letter from mother in law giving permission that me and my partner have exclusive occupation of one of the bedroom
3) a letter from land lord confirming that she is aware of the living arrangements and allow us to live as long as we wish for the period of the tenancy and confirm that the property is not overcrowded.

any advise would be appreciated, thank you. thank

[Zach93]

any help and advise please?