Just for grins I pulled up the HCAD page for a medium sized apartment complex in my neighborhood.

If you have a more long term vision I would go with building a buyers list first becuase maybe they can serve maybe as a  mentor or partners later on. 

That depends on a couple of things:1) How much rehab the buildings need and how much of it you do up front2) Age of the buildings - newer the building, typically, the lower the repairs.3) What areas they're in (i.e. vacancy/turnover)4) Size of the units (2bdrms are better than 1bdrm units)5) What kind of deal you get on them.

A qualified intermediary alone should never serve as your sole guide.  

Window retrofits can also be expensive due to special order sizing on stone buildings.

Search for comps of similar sized remodeled properties that has sold in the lasts 90 days in the same area using the MLS, Zillow, Trulia etc. 

Not so much size as location.See what I mean?

You need to gauge the size of the fish before throwing out the line.

I have also served on a local Historic Preservation Commission (the renovation taste "police" as some unhappy campers refer to it).

If the bank is smaller in size I would even try to call their corporate office and track down a contact that handles the REO department.