Yeah, the departure from Discovery would hamper the casting process for an All-Star season.
But let's see...
Casilda & Casilda (TARLA1)
Fran & Ferna (TARLA1) they would most likely decline any offer but I would love to see them back.
Daniel & Carlos (TARLA1)
Toño & Lili (TARLA2) they got robbed in their season.
Nico & Andre (TARLA3)
Jose & Marisol (TARLA3) I think they broke up after the race but could be interesting to watch them race properly.
Ana Paula & Renata (TARLA4) based only on wiki entry because I still need to watch this season.
Dario & Esther (TARLA5)
Evelyn & Jorge (TARLA5)
Karina & Braian (TARLA5)
Stefania & Felipe (TARLA6) based on early legs and wiki entries.
Christian & Dina (TARLA6) mostly because their previous fame could help ratings.
I think that's a good mix...
(CHI) Nico & Andre (3)
I tried my best to balance out the represented countries
Pretty sure they are from Peru and not from Chile.