Questions regarding spouse visa

Two questions, apologies if asked already - if someone can direct me that would be great.

I am applying for a spouse visa for my wife, I currently live at home with family. My parents are happy for my family to stay with them, would they need to provide proof of ownership of the property? e.g. Mortgage statements / title deeds etc - would this be fine.
I would also like to enquire about the accomodation requirement: currently, there are 6 occupants living in the property (large 5 bedroom semi-detached house).
With my wife and my child (who is turning one next month), this would be 7.5 from my understanding - would this be fine? I intend for my wife and my child to share the same room as me - I'm unsure of this part here. Thanks