Parents Visit - tenancy with friends - Hotel as alternative

[bowcreek]

Hi everyone - Tried looking around the forum but didn't find anybody in similar situation.

I'm sponsoring my parents and niece (12 years) to come and visit me and my wife in UK for a month. We are renting with friends so their name if on the AST. We have a vacant room where my parents and niece can stay.

Doubts I have are :

1. Do I have to give AST copy as proof of accommodation if I say they'd stay with us? Wouldn't the bank statements I'm going to give as sponsor prove my residential address?

2. Would it look negative if they see we have AST with 2 other people already, would this place be good for 3 more visitors be spacious enough?

2. What if I get a cancellable hotel booked for the purpose of Visa but then in reality they stay with us? I'm sure not everyone owns / rents a big enough place to accommodate 3 guests and might opt to book a hotel for guests. Does it sound reasonable to ECO usually ?

Cheers.