We’re looking for Excel models to compare these options and calculate potential net worth in both scenarios.

I've been at this a while and have over 70% equity in my combined portfolio, and I'm over 50 years of age, so I don't look at creative financing options. 

I've found options in Costa Rica, but rates are in the 10% range.Does anyone have any experience or guidance on obtaining a mortgage equivalent to purchasing a 2nd home in the US?

Now we are mostly scaling our business with larger communities but I've used many different creative finance strategies including seller finance, private lending, hard-money, collateral from other properties, and lease-options. 

I recommend comparing lenders to make sure you get some good terms and financing options for your next investment!

If I have several options, I would prefer a HELOC with no initial draw requirements (i.e. to establish a literal line of credit that I have no specific short term plans to use), i.e. not something like the better.com HELOC. 

We have three potential options.The first option is for me to completely owner-finance his purchase.

Once they are leased, then you can take over from there.There are several software options if you want to self manage.

The "non conforming" lending options are actually called NonQM (non qualified mortgages).

We are wondering what would be the best option to do with the property during this 6-7 month period, whether that be Airbnb or what other short term rental options might there be that could make more sense?