I would consider lowering the price or offering some bonuses like 50% off the second month's rent to make your property stand out from the crowd.

One thing I’m confused on is the calculation of the 2% rule.

This is also the notice period for terminating a written lease for anything other than non-payment of rent (unless written lease says otherwise).If you are going to play the game (landlord-tenant), you should know the rules.

It's not conventional financing and the rules are made up by the individual companies. 

Meanwhile, you have the duplex to consider.I don't know South Carolina, but your duplex does not meet the 1% rule.

There are tons of things to consider from zoning and land use rules, utilities and nosy neighbors who may not want "those kind of people" in their area. 

Do you have 50% of the purchase price plus 20% of the construction cost to bring to closing?

I would either charge the tenant 40% of the monthly utility bills or get a estimate of a full past years utility costs and increase the tenants rent by 50% of that cost.

You just have to make sure you get a condo with plenty of room in the cash flow margin, the one thing you can't control is the HOA monthly fee, If you buy the condo with a $200 a month cash flow and your HOA raises the dues $50 next year, then $50 four years from now, your cash flow has been cut in half four years into your long-term Buy-and-Hold investment.

Depending on your state, small claims would probably rule in your favor.