However, there is one tenant we inherited who accounts for 80% of our maintenance calls, most of which we suspect are caused but her two young children.

It currently rents for $850, which is under market for this neighborhood (market is probably $950).With taxes, insurance, debt service, management expenses, 10% for maintenance, 10% for capital expenditures, and 10% figured in for vacancy, I'm calculating a current cash flow of $90 / month based on the $850 rent.I know that's not stellar, but here's why I like it:The neighborhood is one of those neighborhoods I really believe in -- it is minutes to downtown, and central to major redevelopment and transit projects in my city (Atlanta), and it may just be one of these hot neighborhoods that becomes one of the great places to live.Right now, this is the cheapest on-market property in the neighborhood -- the closest comps are in the 85-95K range, and several flips (not comps, but nicer houses on the same block) have sold in the $200K range in the past month.

I wouldn't say these are cash cows, but today I sit on approximately $400k in equity across all properties, and generate roughly $1100 in positive cash flow monthly (before maintenance).I found out over the past 12 years that I actually enjoy being a landlord.  

There are multiple levels of certification depending on how much remediation you choose to do, each certification level comes with corresponding requirements for routine re-certifications.

Unless you find some with a lot of differed maintenance in a bad neighborhood.  

Price $430kGOI: $52,200Taxes + Insurance: $14,600Vacancies / Gas Heat / Maintenance (estimate): $8,250On-site property manager landscapes and repairs for discounted rent. 

.) • Will you consider leasing the property to me with an option to buy if I guarantee the mortgage payments and maintenance?

It looks like you're missing all of your expenses: maintenance, capex, management, and vacancy.Anyway, as @Alexander Felice said, how many banks have you asked the question to?

Yes, the actual mortgage payment may be less than rent, but when you factor in all of the maintenance costs (and your time) involved with maintaining the home, the difference shrinks considerably.

This leaves about $10K to cover all ongoing exterior maintenance repairs, plumbing issues, appliance replacement, yard work, plus creating a reserve for parking lots and roofs.