We have been primarily buy and hold and wanted a secondary source of capital to fund our buy and holds.

At that point you will be using the cash from appreciation/equity instead of your funds.Each time pulling out the intial capital and enough to put down on another property growing your REI protfolio. 

Quote from @Rodney Davis: Does anybody know anything about Signature Capital Group?

I would just cap it generously to only catch abusers and figure the normal running costs in your rent. 

You'll meet a bunch of fellow capital region investors and people who can help.

Those who thrive on this are able to:  Buy low priced distressed properties    /   Purchase properties with manageable capital requirements

With that capital, I’m planning to either dive into a larger multifamily project in Detroit or grab a small duplex or quad in San Francisco.To reach that $500k mark, I’m leaning on the power of cash-out refinancing.

Some folks in my circle also invest in other places like San Antonio or Phoenix, capitalizing on strong demand for workforce housing..

If Costa Rica gives more capital gains like you suggest (which I doubt given how pricey it already is), he's going to get them with his own property and he'll ba able to take advantage of it without needing anybody's consent.I think the question is whether you can lure a lifestyle buyer into seeing it as a better opportunity than if he'd own his own property. 

The process must be understood and applied to team building, investing your and 3rd party capital, and financial deal structure with debt and equity sources.