He does need to meet with each Foreign National client face to face at least once. 

But remember that clause in the lease about how the tenant is responsible for foreign object blockage in the plumbing system?

A few years ago, I spoke to a few wealthy foreign investors that bought properties in "bad areas" in bulk.

Beat all the odds, a foreigner, looking and smelling like a monkey and I made it.If I can be a robotics scientist building exoskeleton robots (think Ironman) for NASA, do you seriously think I will fail at SEO?!

However, all of those things, including the property should be depreciated properly.If all of this sounds like a foreign language to you, that's just one more reason to hire a knowledgeable local CPA (grin).

I did some research into the rules on taxation for gifts from a foreign person and wanted to confirm my understanding (given innumerable loopholes/gotchas in the tax code).

My only question with Costa Rica would be how does the local law protect foreign investors? 

There is a Foreign National DSCR program available.

They will look at a sponsor for the foreign national as a partnership.

Foreign income counts......Provided you did your patriotic duty and paid American taxes on it.Normal continuity of income rules apply.