There’s more talent in the reds backline then there is at the rebels
The position of incumbent wallaby is stupid considering Michael Cheika was the last guy to pick a team.
Let’s talk “form” Players.
To'omua and Koroibete are surely incredibly likely to still start for the Wallabies in 2020 and DHP will undoubtedly be in the squad and a strong chance to also start.
I'd guess Reece Hodge would make the squad again.
Every incumbent Wallaby still playing in Australia will make the test squad and most will still be in the 23. (Sio, Ala'alatoa, Hooper, Naisarani, Koroibete, Petaia, Hodge, Uelese, Slipper, Tupou, Salakaia-Loto, White, To'omua, O'Connor).
The other RWC squad members still in Australia are Fainga'a, Simmons, Dempsey, Kuridrani, and Haylett-Petty.
I would say out of all them, Dempsey, Hodge and Uelese would be the only players vaguely at risk of missing a 2020 squad.