Yes, management is more intensive, and 50 units is nearing the size of facility that having a small on-site manager could be a benefit for oversight, management and leasing.

If you where going to be able to recreate the orginal layout, you would of been able to do so by the clues left behind by remaining framing, be it the "honey" holes where the toliets once where, the sizes of the holes in the joist would indicate what pipes ran where be it hot and cold supply, toliets, showers and other industry standard tell tale clues. 

I've personally explored this myself but my typical transaction  size is $3-$8M and the required check sizes are too small for their services.

The company seems to be a legit mid-sized business.  

Mary’s Counties.)The market here is often driven by government and military employees due to the proximity of Patuxent River Naval Air Station and government agencies in DC, The Southern is known for larger lot sizes, single-family homes, and a mix of new developments and older properties.

As you said, " a 1920's home generating 6k a month is overpriced at 720k" but a 1920's SF home that is smaller than one of the 3 apartments in the multifamily on a similar size lot for $450k makes that $720k option more realistic. 

I would do an average size home for about $300.If this is for a municipality, it will need to be a to-scale, flat 2D drawing for their filing purposes that includes every room - down to each closet.

The only real opportunity for "surprise" is in a situation where the market is split between expecting different sizes of cuts.

You can still make good money otherwise I wouldn't be doing it, but property management is still fairly labor-intensive over a decent-sized portfolio. 

I am currently dealing with headache after headache with the single-family lender who cannot even articulate the reasons why they are enacting their flawed policies meanwhile it’s smooth sailing with the lender for the larger parcel directly next door where the loan is 20x the size.