The math behind Real Estate is not that complicated, Revenue - expenses and debt service = cash flow. 

This includes all charges paid, utility accounts set up, renter's insurance established, lease signed, etc.

Despite facing setbacks, including a year-long renovation process, I tackled the repairs, improved the interiors, and addressed all concerns.

Your not correct under many different circumstances.First property tax is 1.1% (fairly safe) with 2% annual increase (prop 13).Next expenses include a lot more than property tax and interest. 

I already have proof of concept in Raleigh as Ive talked to multiple people (including the agent Im working with there) saying airbnb-ing rooms is a cash cow there. 

For a variety of reasons, including keeping this potential project "need-to-know" only right now, I want to get a ballpark estimate with full understanding that the goal posts could move in either direction as the project gets more discrete. 

The one who thinks that they are masters of the universe in EVERY area of life, has 30 different businesses, claims to be fit as a fiddle, with a life in perfect harmony, shows off huge toys, has 30 different businesses, including selling their time by the hour to provide coaching... this person is not running a real estate syndication business.

Depending on your debt to income, you might have to sell or have an executed lease to secure financing to buy the second home.

There are tons of filters you can use including out of town owners, single family, multi fam, equity percentage…etc. https://www.melissa.com

There is no requirement for @John Gillick to replace debt with new debt.