The nationwide factors that are driving the market apply mostly across the board, and a slack market likely indicates a very large downward trend in that area caused by an outside factor you don't want to deal with.

The condition of the unit is one factor in determining the effort, but the tenant can be a larger factor.  

This does not factor future partnership deals with Cash Providers/private money lenders, just the deals we can do on our own at this point.

At 1/8 share, that's about a 45 days or a month and a half max factoring in 365 days in a year.

Where are you getting the market value and does that factor in all upkeep and upgrades that need to be done to the property?

Both of these factors make it less likely that the property will be able to rent for enough to cover all the expenses (let alone positive cash flow).Additionally, you will need to think about the transaction costs when buying and selling. 

Property taxes usually go up every year and you factor that into your costs. 

With only 5% appreciation factored in (to be conservative), my ROI on my 20% down payments is around 80% on all my properties.

Maybe if you're lucky you were able to negotiate with the other tenants to get those units up to market rent as well, further pushing the value upwards (of which there are a few tricks, although the deal would need to make sense without this factor as it is not guaranteed.

In regards to tenants already being in place within a unit - my encouragement is to not worry too much about this being a LARGE positive factor.