Make sure to get copies of tenant's IDs (so you can properly name them in the event of an eviction) and retain copies of work pay stubs (in case you need to collect a money judgment from them if they do not pay).  

To some degree, under that same idea is why the employee of a licensed Mortgage Servicer company needs to be licensed in order to do that work inside their four walls.  

This allows you to purchase then rehab then retain a property for very little (relative basis) out of pocket.1b.

The back of the home has a hole in the wall and one of the structural beams has been impacted - it appears as if it has suffered some light damage, although nothing major.

Wall Street averages nationwide 31k per door.

Age is only a concern as it lends to condition of the house..are the walls breaking down?

Of the two I can think of off the top of my head, one had a significant black mold issue, the other was a structural issue (I think the former owners pulled out at least one load-bearing wall).  

Many small drywall holes will need to be patched, then every wall and ceiling primed (with Kilz, for the smoke) and painted.

Do the following terms mean installment sale: installment contract, land sales contract, contract for deed, conditional sale contract, seller financing.The seller would retain legal title in all these instances, and the buyer would have equitable title?

I would avoid a house that has most of the walls and electrical/pipes gutted.Many even have a working HVAC system or only require a simple fix but you don't always get that lucky.