Urgent: Interior appraisal required when no interior access?

[Anna Smith]

Hi, 

I am buying a property owner occupied from a bank foreclosure with $22K deposit at risk without contingencies. There are apparently squatters there and they won't allow access and bank requires I give them 30 day notice and only after closing before contacting them. I attempted contact by ringing doorbell (thinking they probably would appreciate more notice than less) but no one answered. From exterior I can see there is someone living there as there are cats inside. 

I am attempting to obtain FHA or conventional financing. Lenders are telling me that an interior appraisal is required. I have sold properties before with an exterior only appraisal and did equity lines same way, so I need to know what are the exceptions to an interior appraisal when no interior access so I can close. I have 30 days to close.

If interior appraisal is required, I would appreciate any feedback on how to look for a lender that will allow owner occupied sale with private money or less strict terms. The house is being purchased 70 cents on the dollar so has good LTV. I am hoping to close with 5-10% down though so conventional with long term low rate would be optimal.

Thank you!

Anna