Spoilers Ahead!
I did some analysis of the montage they showed at the start of episode 1 (have not yet finished the episode, so there could be more confirmation of tasks that take place in Salta besides the carnival that are not referenced here), and there were pretty heavy spoilers! I tried to identify as many of the backgrounds as I could, but, to be safe, I've left out any information I'm unsure of. In assigning leg numbers, I assume locations follow the same pattern as the last few seasons, spending 3 legs in each country.
Safe to Phuket (Legs 10-12)
* Bam Bam & Logan
* Brooke & Adam
* Pete & Bridget
Images grouped under Phuket include the various shots of Ko Panyi, Ko Rang, Phang Nga Bay, and teams washing Asian elephants.
Safe to Namibia (Legs 7-9)
* Thorpie & Christian (there’s also a shot of them kayaking in what could be Phuket)
* Billy & Oscar (at an eating task in Swakopmund in the Live Sightings Thread)
Images grouped under Namibia include teams sandboarding and climbing up sand dunes and teams interacting with Bushmen.
Safe to South Africa (Legs 4-6)
* Havana & Steph
* Chloe & Emily
* Jett & Lily (Seen in Johannesburg in the Live Sightings Thread)
Images grouped under South Africa include teams on a safari excursion (lions seen), Bam Bam & Logan dancing with Zulu (?) tribesmen, and teams at a school/orphanage, including the extended Chloe/Emily speech to a little girl.
Safe to Jujuy (Leg 3) [Jujuy is not confirmed but Thorpie and Christian are shown marveling at Quebrada de Humahuaca in Jujuy Province]
* Cyrell & Eden
"Jujuy" is how I'm referring to the rocky/deserty clips. We mostly seen Cyrell & Eden in these shots, dealing with a donkey and carrying items on their backs.
Seen in Salta (Leg 2)
* Nat & Mel
Salta was defined as a foresty/marshy background; the main shot featured two teams running to the Pit Stop and Nat & Mel walking to what I presume is the Pit Stop. I've traced Lily's "I can't, I can't" freakout to Salta based on the background and the preview promising an eating challenge.