ILR Interview in Croydon soon. Help!

[Bara]

I’m Japanese and married to a British citizen. My husband and I are going to Home Office in Croydon for an interview for my ILR (after 2 yrs spouse visa) early next week. It’s been frustrating 7 months since I applied for ILR so I am trying to have everything prepared for the interview. I really want to have this sorted asap.

We believe the reason they want to see us is because we could not give them many home related bills. This is because we are staying in a place which my mum-in-law is renting from the housing council. She is disabled and is not paying for rent at all.
We do help her financially and physically and explained the situations when I sent the application but they probably still think something is not clear.
I will take many photos, my bank statement (certain amount of savings), letter from our church, etc, etc.
I would appreciate it so much if anyone could tell me what kind of questions they will ask us etc…
Any advice or info would be big help! Thank you