From the John Locke Foundation article linked above:
The city is planning for ticket sales and other theater revenues to raise enough funds to pay expenses, including Parton’s $1.5 million annual fee and the monthly debt service on the $21.5 million. If those funds are not enough, the city will have to use local sales or property taxes.
(in the South Park's Sheila Broflovski voice:) What what what?!
Who in their right mind thinks Randy Parton playing four nights a week will generate $23 million? I'm not so sure they could make that much money if Randy's sister Dolly was the nightly headliner.
The city fathers of Roanoke Rapids may have an answer, but they are keeping that a secret. The article notes that the financial statements for this taxpayer-funded project are considered confidential. They consider them to fall under the category of "trade secrets." Sorry, but anyone who think the finances of a taxpayer-funded project should be kept secret from the taxpayers should be run out of office immediately.
Parton's production company is supposedly responsible for making payments on the city's loan is well named. However it is unclear if they are on the hook for anything if their profits don't cover the city's costs. Since after all the agreement is confidential.
But we do have a very strong clue to these answers from the name of Parton's production company, Moonlight Bandit LLC. Although they are somewhat misnamed, as this robbery is taking place in broad daylight.