I know after this I have no profit, but the tenant is paying the majority of my Mortgage, taxes, and insurance. 

You're not only losing money from cash flow(-), but you're losing potential profits from an investment that wasn't taking away your profits...and your seed money at the same time.Those profitable returns you're losing, is (should be) exponential. 

As an example, for a 20 unit apartment building we would need to hit $100 profit per door per month after debt service to hit our yearly cash flow goal.After purchasing the fifth business (year 6) my business partner would retire and keep their half of the yearly profit (~$60k) and I would switch from adding new businesses to using the snowball strategy to pay down the debt on the 5 businesses.

Key is to clearly define the partner obligations and profit sharing, etc.

Even if the profit margin is smaller I'd rather hit many singles than hit a single home run.

Because I've seen quite a few calculators or articles excluding the potential tax saving on the interest payment, which obviously would have a big impact on the profitability of the operationsWhat's your view on that?

So long as the numbers work, there is still a profit for you and there is a good exit strategy, you should be able to find someone. 

You need both money and know-how to invest profitably in any investment, specially real estate.2.

The profitability of this property is in the: Depreciation, property tax , mortgage interest & principle pay down.  

I'm surprised that more investors don't look into student housing like this where they can charge by the room and increase their profitability like you're talking about.