Do you mind me asking how much you would need to replace your income?

We have a reasonably high income from our W-2’s and rents with annual income in the $250k+/year depending on bonuses & OT worked and is usually closer to $300k.

How do I calculate interest income, what are a few tenant charges (income), and expense reimbursements.

Do it yourself with TurboTax (or similar software)If your rental is pretty simple (one property, basic income & expenses), you can learn the basics and still save money.

I'd estimate that there are less than 1,000 legitimate, or "professional" wholesalers, in the United States of America, as defined by individuals who make $100K flipping contracts, and collecting assignment fees, in any form, and who have made that amount of income more than 3 years in a row.

As you mentioned intentional flips are typically considered inventory-This means the income is ordinary income and as such: - Is not a capital gain, so hold time of 1 year does not change to a better long-term capital gain rate - Can not be invested in a QOF Deductions related to it can't be pushed or changed- all costs are accounted for with the inventory component 

Income tax and local taxes.

Less than $300K in a mortgage, generating $4,000/month in rent.

The frameworks others have presented of viewing the site as a lead-generation tool where you, as the host, are handling all the payment processing and screening is pretty accurate. 

For example, I mention that every adult must pay a $30 application fee, pass my credit/criminal background, make a combined income of 3x the rent, and whether or not the property accepts pets.