You will pay taxes on the Net Revenue or profit after your expenses, which will be your Income.

Any damage to the Premises (including, without limitation, concrete walkways and stairs) caused by Tenant's use of ice melt, salt or similar product shall be the sole responsibility of Tenant, and Tenant shall be responsible for the cost and expense any repairs required as a result thereof."

If you have an understanding of real estate and think you can get better results growing your retirement savings in that asset class, then a self-directed IRA or Solo 401(k) is a means to do that.All investments are made in the name of the plan, all expenses come from the plan, and all return accrues to the plan.There are several different plan types and service models available.  

Duplexes get extremely expensive and you will be fighting many buyers to get one.

Matthews IV - @Natalie Kolodij is correct, working with two professionals can be a bit of a pain on the client end and can get quite expensive when you have two professionals not only trying to create their tax strategy for you, but then also working behind the scenes to discuss strategy with the other professional to make sure they align.  

You need a new property manager.The "50% rule" is a rule of thumb that say of the gross scheduled rents, expenses, vacancy and capital expenditures will eat up about 50%. 

If you guys want to come out my way in Brooklyn, basically near Prospect Park, I would be happy to meet with you.If you read my posts and my background, you'll find I have 2 decades of Real Estate Investing history in Brooklyn.I currently own 7 multi-Family Investment properties, generally 3 and 4 Family buildings, in Bed-Stuy, Clinton Hill, Windsor Terrace, and Ditmas Park, with partners.The total Assets are worth over $15 Million.If my strategies are not necessarily aligned with yours, at worst you will walk away with an understanding on how to be a successful buy and hold Investor in a highly expensive and appreciating market like Brooklyn.You don't have to invest my way.

The deferred maintenance might also account for more than a $2k on annual expenses.

I would want an 8 cap min for a solid investment given the building is old and more expensive to upkeep, but it is likely the prices will not be that competitive in that neighborhood.

I would sell before the expenses push you into serious negative cash flow.Unless your rent is in the $2000/month range your are headed down a rabbit hole.