There would be a many unknowns compared to a property that was completely occupied. 

We had originally thought that Bob could lien the property for the construction costs, but, the profit will be directly related to what they end up selling the property for, which is usually an unknown until the final hour.  

From my experience (at least here in Louisiana), the thing to remember is that you don't get the opportunity to inspect the property physically prior to closing.I have been pleasantly surprised and the I have also been "unplea$antly $urpri$ed"If you're the winning bid you assume the risk of the need for an eviction, a title lien, or unknown repairs required.The newer the property the more likely (it seems to me) you may have these risks of unknown liens or need for repairs.I would do it again, but I will only buy at 60% if ARV.

There are still a lot of unknowns due to the fact we just started looking into this today.

For this fact alone I your default has to be there is unknown hair on the deal.

One was on the market and is under contract with a seller (price unknown), the other two went through foreclosure and are on the market (one at about 10% below what is owed, the other about equal to what is owed).

I mean why would you risk to venture to the unknown.

If you've never done an apartment deal before or you are an unknown to the broker, you may be ignored even if you submit a full price offer.

Things to consider there would be impact on working capital, uncertainty around 'unknowns' (more risk needs more reward to compensate), and your comfort level and liklihood of a kind of worst case. 

@Dave Passey But still you can’t stress about the unknown.