For island #4 I assume you’d need to choose a Treasure that could actually be loaded, as opposed to one that would go face-up on the island?
Correct, it’s in The Pirate Code now on page 11, I believe in part due to ziotoo4’s Creative Fleet Challenge entry back on MT.
Another UT to farm with the canoes would be Lost. Being able to place trade currents all over the map could set up some really easy logistics, or maybe place terrain under a ton of enemy ships. (could also be a way to “hack” the terrain setup meta if an opponent votes for 0 terrain and gets the d6 rolloff, then canoes hoard Lost and yank in 1-2 dozen terrain lol)