Some people are sending supplies (clothes, other needed items like school supplies, food for humans and pets, etc). 

This property needed an extreme amount of clean up and haul away of items left behind.

Here's the issue...in most states, if the tenants have a lease, the new owner will be obligated to honor the lease - as is - until end of lease. 

I advertise via Sabbatical Homes and Harvard Off-Campus Housing and insist my leases begin on Sep 1, Jan 1 or Jun 1 and end on Dec 31, May 31 or Aug 31. 

Common fees will include a set-up fee, a leasing fee for each turnover or a lease renewal fee, marking up maintenance, retaining late fees, and more.

But once I got the bills, I increased the rent with the tenant's approval and signed an addendum to the lease stating the rent increase would be X and the owner would take over utilities.

Tailor these amounts to the significance of the task; for example:Roofer: $1,000/day (critical to weatherproof the site).Painter or garage door installer: $100–$200/day.Contract Value & Payment Terms:Agreed payment amount (lump sum or itemized costs).Breakdown of payment terms:Deposits.Progress draws.Retainage (if applicable).Scope of Work:Be as detailed as possible.

Originally posted by @Mike Cumbie:Question 1 is do they have an existing lease?

If not, I'm guessing it would be treated as a traditional rental loan, either conventional or DSCR, using market rents rather than the rent in the lease agreement.

To evict a tenant based on a lease violation such as hoarding would require you to notify them and then give them an opportunity to fix the situation.