Antarctica does have permenant residents, granted its a collection of other cultures from around the world.
I just brought it up since it is a continent, it would more be a pavillion about history and science and scenery than culture. But theres still more than enough information and things to talk about to fill up a pavillion.
the staff there could pose as researchers from around the world.
and as antarctica doesn't have its own government, disney could fund the pavillion to add to the world showcase, without it being seen as a departure from requesting some finacial support from the country being represented.
They could totally do this WS side expansion and have it be continents rather than countries. The continent pavillions could be focused more on history and science, and rotate thru the cultures of the countries they represent with the support of the countries, while the individual country pavilllions would continue to be country supported, this would give even small countries a chance to be represented without a huge fiscal long term investment.
That would save the southern Lagoon expansion for additional countries.