A pitch for the general land direction...
A very, very, very weird and unique combination of this, this, and this:
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This might seem crazy at first glance. I will explain my reasoning for each "theme" below.
First off, we've already established the natural environment will be unlike any Adventureland seen before. It will be inspired by the unique flora of Madagascar, with tall baobab trees and the like. This will set the land apart from anything else. There will also be a great misty fog surrounding the island.
Second... I suggest instead of the "settlements" being European, I suggest this settlement be done by the Ottoman Empire. In the backstory
@PerGronStudio mentioned it was Arabic traders who actually made the journey in the first place. This makes the land even more visually distinct, and ties to the backstory. We have Islamic / Arabic / Turkish architecture, building up into a forced perspective of a Grand Palace at the center of the settlement.
But that's not all, the town would also have a distinct "steampunk" vibe. There wouldn't be any airships or the like, but it would clearly be approaching modernity with hastily constructed pipes around the buildings and steamships docking in port.
All in all, this would make for one of the most visually distinct lands seen in a Disney park... ever.