If we need customized items, like a Leasehold DOT on an airplane hangar portfolio, then we (borrower) pay extra. 

I understand what you are saying in terms of having to pay the extra 650 $ a month.

So yes no capital gains tax, and didn't put any extra principal payment.

But remember that what is favorable now could come unfavorable in the future as they readjust over time.Reasons many landlords avoid vouchers include the hassle of the extra inspections, the perception of a worse tenant, and maybe the inconvenience of getting rent from two different parties. 

I had an empty LTR that was unfurnished and they paid an extra 650/month and also paid to furnish it for a 6 month rental. 

Everyone needs to be extra careful and do their homework.

You don't need to add the extra step of doing a cashout refi as you aren't keeping it and it costs a lot of money to cashout refinance.

The dollar-peso exchange rate benefited us with respect to fees, so we have some extra class A shares we can use as collateral. 

I did a survey last year and spoke to 8-10 lenders and they all said they wouldn't add extra value to the property based on it being a working STR.You need to check comps of other mobiles in the area of similar quality and price it accordingly.

Just pick a route, get extra liability and focus on growing.