In admittedly oversimplified form:Say an identical 10-unit building a block away, where the units all rented for $1k/mo ($10k/mo or $120k/yr PGI) sold for $1M.

A quick google search could help you identify the enforcement terms during your initial due diligence but you will want to verify before you close on the note. - For closing, first you will sign a loan agreement to determine what the seller will record, how much they will expect, exactly what you are paying for, and who will service the loan.

@Ryan BlakeI am still doing the due diligence on verifying the income/expenses as well as general condition

Verify every piece of info you get.

Must have references that are positive, employer that is positive (or verifiable consistent income), 1st last and security, and complete background and credit check. 

As for buy and hold, you’ll buy at a discount and the concern will be the quality/completeness of the remediation, which is almost impossible to verify..

let's say i am looking at to identical house, where each one of them will produce $500/month after refinance.

I haven’t done my own due diligence to look deeper into this, and verify for myself (so maybe somebody else can shed some light?)

@Mike AllisonDuring the due diligence I should have pushed harder to verify security deposits and rents with an addendum signed by tenants.

(usually verified by the appraiser, particularly for FHA & VA).Will the buyer's lender allow the assignment of contract?