Updating this thread for posterity that the 6th ship has been announced as the Disney Treasure, with Jasmine/Aladdin/Magic Carpet in the atrium and an overall 'adventure' theme.
One interesting line from the
blog post about all the D23 announcements:
"The Disney Treasure is scheduled for delivery in 2024. Following the Disney Wish, which set sail in July, it’s the second of three new ships planned through 2025. The Wish class ships are powered by liquefied natural gas and feature 1,254 guest staterooms."
Notice that the article refers to 'the Wish class ships' -- are they abandoning the Triton class designation, is this just someone who didn't do their research, or was this a conscious choice for the article because they thought calling them Triton class would be confusing?