How payments get from whomever is making the payments, to the underlying lender varies by agreement. 

My COC return will vary depending on my out of pocket cash.

However, private financing options are becoming increasingly popular for scaling portfolios.Zoning and restrictions: As you mentioned, regulations for short-term rentals, such as Airbnb, vary significantly.

When I looked at prices recently they look like they've gone up quite a bit but I know they vary a lot depending on the neighborhood. 

I've included an example below to help illustrate this.So different lenders have different rates (which do vary even for DSCR loans) but these are factors they all consider.See example below:DSCR < 1Principal + Interest = $1,700Taxes = $350, Insurance = $100, Association Dues = $50Total PITIA = $2200Rent = $2000DSCR = Rent/PITIA = 2000/2200 = 0.91Since the DSCR is 0.91, we know the expenses are greater than the income of the property.DSCR >1Principal + Interest = $1,500Taxes = $250, Insurance = $100, Association Dues = $25Total PITIA = $1875 Rent = $2300DSCR = Rent/PITIA = 2300/1875 = 1.23If a purchase, you also generally need reserves / savings to show you have 3-6 month payments of PITIA (principal / interest (mortgage payment), property taxes and insurance and HOA (if applicable).

The rules and payment standards vary significantly from one area to another, so familiarizing yourself with the local housing authority's procedures is key.

Yeah, again, simple right.Now doing a tenant placement, the efforts, advertising, the actions to get it best done DOES vary in relation to the rents.

Return on Investment (ROI):A good ROI on a fix-and-flip can vary by market, but a typical target is around 10-15% of the ARV after all costs (purchase price, repairs, carrying costs, and selling expenses).

It's very personal and varies wildly. 

Also, do hard money lenders vary from states?