Generally, until the lease is signed by both parties, anything can change. 

Work with a professional 3rd party PM who already manages dozens or hundreds of S8 units and is on a 1st name basis with the local case works/housing authority folks.

It os always nice to work with a seasoned pro on the other side, because you can count on them to negotiate a reasonable solution for both parties. 

Before you say "I am a fiduciary" please go submit your ADV or regulatory documents to the Institute for the Fiduciary Standard as I have and get third-party approval that you are in fact a fiduciary. 

The hard part is knowing how much you will make over the course of a year.

If they decline to share, that is a red flag which would warrant walking away or at a minimum substantially reducing the price instead and basing the offer on your own numbers validated by third parties.

However, as the property owner, it's ALWAYS prudent for the other party (tenant) to have some of their OWN skin in the game.  

I've thought of 3 different approaches - 1. co-borrow...multiple parties on deed, entitled to % rent & depreciation based on investment, have "access" to property2. co-sign...multiple parties not on deed, negotiate % rent & depreciation based on investment, no legal access to property3. side-deal...parties gifts the down payment, operator must qualify for loan, all other details TBDAre there more approaches/options?

The problem I find is I don't like putting in that much time doing research and field inspections (300-400 properties per week are auctioned) for such low odds that the property will sell at a price I need it to.....either the plaintiff will have a really high max bid set (like the full judgement amount) or another 3rd party bidder will bid it up more than it's worth.  

Talk to your PM to talk to your insurance and tenants.Get a 3rd party adjustor to take a look at it, make sure the tenants are re-housed on the insurance companies' dime.