While I admire your desire to help people, at some point, that is going to bite you in the ***.You should have firm set criteria, and stick to it.

I dont have the full purchase price of this 4plex to invest though, so I would have to finance half to 2/3 which seems like a stumbling block. i can still make the numbers work, but at a much lesser monthly profit i suppose. i also dont have the w2 income to support 2 mortgages (counting the one i have on my house), so i assume any bank would have to count the existing leases towards my income which i understand is possibleI guess I was wondering about advice, or red flags, anything, on this specific deal.

For local specifics, I would recommend starting with the Arizona Landlord Tenant Act.

@Larry Cersosimo,It is not possible to use your 401k as collateral for the loan, IRS specifically prohibits this. 

Some lenders might require a specific residency.

However, it does come with some specific rules and procedures to follow.

You can also download a lease specific to your state through Zillow.

Just to be clearer, I don't mean the method that tenants set up the autopay or Zelle in his bank account, but some method, app or digital platform, that debits the payment from tenant’s bank account at some specific date of each month, and It sends it to my bank account.

Of course what he’s doing is creating a book of private “listings”, tying them up at a specific price for 90 days, and only closing if he can flip the contract for a higher price to an end buyer.

Figure out your investment style first and then you can ask more specific questions on different ways to achieve that goal.