We'll see what actually happens, but all the people I see mentioned are strange in their own ways:

Hyundai - (note that they were they highest scoring team in South America, so why change now?)
Mikkelsen (for Loeb) - While dropping him for Corsica was logical for multiple reasons, this wouldn't be. Dropping after 1 bad rally (in last 9 months) where he still outscored both Toyotas and just after getting 2nd place ahead of Ogier. Portugal is also much more similar to Arg or Mexico than Chile and he always did good there.

Sordo (for Loeb) - He was slowest Hyundai in Argentina and not the fastest in Mexico, but can hardly blame him for the technical issues in Mexico and also on one SS in Argentina (that cost him 5th at minimum). He is typically the most stable 2/3 driver at Hyundai (Loeb included), has driven in Portugal the last few years and it's almost his home event.

While Loeb had level playing field in Chile, in Portugal he would be at quite some disadvantage since majority of stages are same as last years (and some of the new are known from tests). Also if he doesn't want to (or is not paid to) do more than 6 rallies this year it would be strange to "waste" him in Portugal where both other drivers are likely to do ok, while in multiple other rallies (GB, Spain, Germany, Finland) one or both are risky.

Citroen
Lappi (for Østberg or even Breen) - Yes he has had 4 bad rallies in a row. But he also did 2nd place in Sweden and Citroen is clearly not aiming for manu titles so don't see how it matters. Furthermore he signed for 2 years, dropping him for a rally this early would not really set good atmosphere for remaining 1,5 year.

Toyota
Latvala (for who?????) - He hasn't had a good rally in the 6 rounds so far, only Argentina was kind of mediocre (5th place), and only 1 clear technical issue (Mexico). But there is nobody around that can really be expected to do better in a Toyota on such a short notice.

Meeke(for who?????) - Also no really good results in the 6 rounds so far, 4th place from Argentina is decent though. But same as for Latvala there is nobody around to replace him.

MSport
Suninen (for who?) - As I understand he brings the money to drive the car, so I see this as impossible.