Redemption Island truels. Because Redemption Island will have two people to start, and a third will join after the first episode, duels will feature three people, so they’re actually truels. The loser goes home.
Redemption Island swap redux. The swap isn’t just for the opening first-impressions vote. Partners can swap in at any duel, and based on Dalton Ross’ reporting, it sounds like they may be able to decide to swap after getting a sense of the challenge, so the pair can decide which of them is better off in that particular challenge. That also means the tribes may continually change.