Even if you don't have a great idea, if they tell them what your goals are they can often take the blank space, add the walls, fixtures, etc. and give you something that reflects your needs.I've worked with a few clients where that was the case.

Entire back wall was unsupported and we had to dig it out ourselves to keep the cost down.

I think your condo is underinsured--the less the square footage, typically the higher price per square ft in general because more of the house is bathroom kitchen walls...etc rather than open air.  

Either it was a building only sale or the property lines were drawn to show the divide bisecting shared walls.

The house is lower than the street level and that got me worried about water.After the first visit I observe the following:    ROOF:- Owner says that the roof has been redone in 2014 and is in good shape.BASEMENT:- There is a drainage canal around the walls connected to a sump pump on the corner.

If you see on the first property I was able to get rid of both walls and on the second property I was not able to get rid of the entire kitchen wall and very little of the wall between the dining room and living room.

There is no HVAC at all in the house; the previous owner, who was rehabbing it when the housing disaster hit, installed electric wall heaters to save on cost, I think.

In terms of the goal, if I understand your second questions correctly, we would prefer to sell off all of the units, ideally by building instead of individual units, and retain zero ownership and equity.

Add a small arbor, attached to the house, on the big blank wall to cut the height of the windowless wall, similar to what you might do over a garage.

Someone earlier mentioned off market deals, I would go with that route so that you can start finding deals below market value, and also consider a value add... not sure if you would be open to minor rehabs, but if you can buy an off market deal for a good discount, and then say add a wall and closet to turn a 1bdrm into a 2bdrm, you can add some serious rental boost to your property.