You need to start the eviction and only stop/delay when you have proof that they have started this process.

They don't care what "theoretical rents" are, but rather what is actually collected.

I here often that proof of funds is required to even see the property.

Collecting money from a deadbeat who skips town has a very low success rate. 

As other have identified, you won't be able to collect for any damages as I rented to a Canadian citizen who was a great tenant for three years till he did not pay for three months and quietly vacated the property.

., as noted, if you want everything to be above board: collect a W-9 from everyone you hire.  

After completing the renovations we plan to refinance and then hold long term to collect cash flow!

You can ask for generic suggestions - "What kinds of companies are out there that do rent collection?"

I think you'll be able to log the income for taxes without a problem; just track them, have proof, and get that info to your accountant. 

If you do need proof, just post a notice for a mandatory inspection and then take all the pics you need of dog hair, bowls, kennel, what have you.