It could be a great solution to the problem but try to verify this prior to making the decision.  

Non-Owner Occupied - so far, I was told that underwriter reqs for this one is at least 20% down (which I should be able to cover but was 'denied' due to the fact that some of the funds are coming from accounts that have less than 60 days of verifiable banking history?

So I'd want to see rent rolls and if possible, verify the rents with the tenants.DON'T FORGET to get estoppel certificates from the tenants before closing!

Our thought was since we are going through this exercise we might as well ask for the invoices to verify what was charged since our landlord was known to be extremely frugal and try to nickel and dime everything. 

Preferably, you get a copy so you can verify. 

Read your contract carefully (both of mine were identical, just names switched out) because there are important deadlines.Good luck

Will they use pay stubs or will they call to verify?

I was trying to refinance my home that was owner financed we almost had it done  through Quicken Loans but there was a problem trying to verify the on-time payments I paid on time for the last four years but because it didn't know that you're supposed to keep all the records and my lien holder is from old school and she did not want nobody to look at her bank statement that shows that we  have been depositing monthly payment into her bank account every month is there anything or any company out there that can help me to refinance my home.

To be sure verify with your accountant.

Verify water drains quickly.