Check to see if any major expense items are coming up, and they have sufficient reserves. 

I  also thought that the insurance, taxes, as well as the current leases can be figured out during the buying process/due diligence and that something can be put in the purchase contract regarding what to do with those items going forward.

In most cases, you are correct in that you need to submit documents to the tenant within 21 days of them vacating the property, but there is a clause in sub-section (g) that states you must provide an itemized breakdown of all charges against a tenant's security deposit:"(g) (1) No later than 21 calendar days after the tenant has vacated the premises ... or not earlier than 60 calendar days prior to the expiration of a fixed-term lease..."

These are the big ticket items that will significantly impact cash flow. 

There are openings in the upper west exterior walls where electrical conduit was removed.10.The stucco in these areas has not been repaired to prevent moisture penetration and deterioration.11.The front unit has issues flushing the toilet, which was confirmed with a tenant, so camera scoping of the drain pipes was performed that revealed damages and blockages in the pipes.12.Deferred maintenance on multiple items: cracks around windows and pipes, gas pipes are not supported, pilot lights in heater units were not lit, a water heater unit has no ventilation.I hired a plumber to scope the pipes (please see his report in the invoice attached and photos); a roofing company was hired to assess the damage to the roof above the middle unit only (please see proposed work sheet); a general contractor has inspected the settlement of the wall in the second unit due to the damaged frame.

Now, you didn't mention CAPEX (expensive items such as roof, HVAC, hot water heater, etc.). 

My mortgage to income (>40 of my income was going to my mortgage) would leave very little room for fun items or unexpected expenses. 

College students are not the best at taking caring of expensive items.

Invest well and don't lose moneyItem 1 is far more important than item 2 for most people.  

Many items are simply removed because there is no way to actually clean them.