I think there are quite a few spots yet to be sorted for the first test against the Saffas, not just 10 and 15.
Hooker will be between Porecki and Fainga'a. Most on here are suggesting Porecki but FF (Folau Fainga'a) probably put in the best No 2 shift by all comers in the first Argentina test. I would stick with FF (Folau Fainga'a) as the starting No 2 next week as his stronger play will be of benefit against the Saffa forwards.
Bench THP is a real concern, and has implications for the bench and starting LHP spot. Options at THP on the bench are Tupou, Fa'amasili, and Slipper. Given Tupou's poor form and Fa'amasili's inexperience, Slipper would probably be the best option against the Saffas. If Slipper stays at LHP, the decision between Bell and Sio on the bench could go either way.
At Lock, I don't think Arnold did anywhere enough to retain a spot. Our Locks have been one of the brighter aspects for the Wallabies in recent times. Back to Swain and Philip to start with Frost off the bench for me.
Holloway will probably get another chance at 6 after a strong first test and a rather ordinary second. Rob Leota off the bench but will come in quick smart if Jed doesn't play out of his skin.
Fraser McReight is an out and out No 7, but is that the way Rugby is played at test level these days? Especially by the Saffas?
Wouldn't surprise me to see Samu start and Fraser miss out altogether. But if Fraser plays, I hope he has a blinder.
Is Rob Valetini the only forward currently sure of starting in his best/preferred spot?
A lot of support here for Gordon/McDermott at 9. I reckon White will be the starter against the Saffas for his experience, defence and box kicking.
What to do at 10? Hodge is versatile and safe at 10, and has possibly the best winning record of all recent players in that spot (maybe QC (Quade Cooper) excepted?). Alternatively, Hodge could start at 15 where there is another big problem, or remain on the bench. I'm starting to think he is being somewhat wasted on the bench when he can play either 10 or 15 probably better than any others in the squad. Kellaway probably offers more at 15 than Lolesio does at 10, so maybe Hodge at 10 is the go.
I am not convinced that Paisami will just walk back into the 12 spot. Foketi looked better than average in a very poor team effort against the Argies and he and Ikitau look to have the start of a good partnership/combination in the centres. I'd stick with Foketi.
13 no question - Ikitau.
11 no question - Koroibete.
14 Wright for my money. Strong winger out of position last start at 15. Vunivalu imo is too green and untested to start against the Saffas. Should have been given time against Argentina.
15 Kellaway. Ditto comment for Campbell as for Vunivalu.
So, I'd be looking at something like:
Slipper, Fainga'a, Ala'alatoa
Swain, Philip
Holloway, Samu
Valetini
White, Hodge
Koroibete, Foketi, Ikitau, Wright
Kellaway
Porecki, Sio/Bell, Tupou, Frost, Leota, Gordon, Lolesio, Petaia