It’s about proving you can return their investment.

By accelerating your depreciation schedules, you reduce your taxable income which in turn increases your operating cash flow.

The goal is to ensure that the property remains viable even if circumstances change, like dealing with a non-paying tenant or a market downturn.

Now it appears your cleaners might be cleaning non-STR properties also (home owners).

If he doesn't need the cash now, you could also negotiate a split you're comfortable with to get him the return you and he feel he should have at the point you refi when the balloon payment comes due. 

We can even return deposits through them too. 

They should be able to determine the COC, annualized return, estimated ARV of a BRRRR, accurate rent comps and more.

The account does not have to be an interest bearing account but if it is, then a portion of that interest earned has to be returned to the tenant annually.

You get a Capitalization Rate (CAP Rate), which equals your annualized return by dividing the Net Operating Income (you had gross in your narrative) by the purchase price.

The value of the property and how it’s distributed relative to ownership stakes will determine whether it counts as a taxable event, I believe(I’m not a CPA or attorney).