Direct ownership?  Any indirect and/or constructive attribution?

Do US persons (whether individuals or entities) own more than 50% of the foreign corporation in aggregate?

What is the entity type of the foreign corporation?  Are the liabilities of the shareholders or partners limited?

Does the foreign corporate actively runs the resort as a ToB or merely invest in it?  Is that the only income the foreign corporation has?

I would ask your clients these questions but there could be a whole lot more.