I compared it to three other units I could find that sold or were selling in a similar condition based on price per sqft.

These are notoriously challenging to predict because of unknown factors that could arise.I'd have to say looking at market conditions and what is expected in your local market can give a good insight to short term property value appreciation.  

What condition is it in?

I would be careful about making any offers until you see the condition of the other unit.

If you choose you could advertise for a replacement and make sure he understands he must keep the unit in immaculate condition. 

Mine has knowledge of the condition of most HOA's in my market and passes that info on to me. 

I think for most people, the lot size is secondary over the house size and condition.

Those are cases where the assessed value is well below the true value.Other risks are fire, building collapse or demolition (that is a real risk in Baltimore) bankruptcy, IRS liens, condition of the property, the hidden costs and not knowing the rules.

I have to agree,those numbers are terrible.You can do much better and should get at least 10 to 12% COC by looking elsewhere like Cleveland or Indianapolis for a duplex or triplex.If you can't raise rents and/or lower your repairs to 5% due to old or deteriorating condition,let someone else eat this turkey.

Average-Good condition)Rehab = About 20k will meet with GC to get better estimates In to the house = 70k (not sure if this comes after total expenses or not.. sorry)Holding Cost (estimated 4 mo ) = about $4300 plus utilitiesClosing Cost = $2900Now in to the house (After 4 mo) = 77,200 plus utilitiesSelling Costcommission = $6600 (6% of 110k)(Maybe) buyers closing cost = 6,600 (6% of 110k) If I'm not missing anything and my estimates are correct I'm left with 26k minus utilities I hope this is considered conservative.