This isn’t really a big deal though.Rent payments can be abated over unresolved maintenance issues and tenants failing to abide by S8 requirements.Many S8 housing commissions will not hold tenants accountable for damages they cause (tenant is supposed to repair or lose their voucher).

Taking the market rents, accounting for a 10% vacancy, the debt service, PM fees and everything else, it seems like I should be able to cash flow about $600 for the 4 doors combined.

The accounting function is very good too, especially for someone like myself who is not exactly a numbers person LOL.  

You can't hold them accountable to the terms if they aren't on the lease.I would remove all of them from the rental and start fresh.

.,) and use QuickBooks for everything related to accounting/financials.

Do you know that most people have about $1k in their bank accounts and the average american has about $5k in CC debt… You are doing well my friend and time you appreciate yourself for it!  

You can set up an online account to monitor the bills and tenants payment activity.

Failing to budget correctly for repairs or not accounting for unexpected expenses can cause you to go over budget.

If so, follow the lease and post the charges to their account or something.

It has an accounting section where you can log expenses and earnings