Is there a good percentage I should use to calculate these numbers (i.e. 10% of total rent should be allocated for repairs)?

This amount is roughly what i've got allocated into the budget but am willing to negotiate to get this deal done.A little background...they are paying below market rent in a generally sought after area (East Nash).  

I would sell the home and allocate the funds elsewhere.  

Managers of higher-education endowments now allocate a majority of their assets to alternative investments, according to the National Association of College and University Business Officers.Many wealth managers advocate real estate as part of a larger portfolio strategy due to the high expected returns, low volatility, and lack of correlation to stocks and bonds.

Be sure to properly allocate your allowance. 

It is a triplex, so the taxable gain will be allocated between the three units. 

Your closing attorney or settlement company will handle the proper allocation of funds once they have a signed addendum on how buyer and seller have agreed to handle it.  

Some of the fees you listed above are inaccurate, and as you already know, some are allocated towards the buyer or seller only.

My quick back of the envelope analysis is to allocate 50% of EGI as OpEx.

@Matthew AlexanderYou should allocate the expenses over the period that it was considered a rental property.One other thing to consider is that you may want to consider selling the house within the next 3 years(2 years from now) to get the benefit of excluding up-to 250,000(or $500,000 if Married filing jointly) of gain.