If Cook doesn't backup and Billy Brittain starts, we have 3 main options
Play him in our 17 , whatever else we do with our team
Play him outside our 17, whatever else we do with our team
Play him at 18
If an origin player (other than Murray, who plays in the same game) doesn't backup, we can use them as loop candidate
If Brittain doesn't do well, our options to play in his stead will pretty much be Xerri, maybe Sivo, or anyone we have traded in
If all origin players backup, we can use Hudson Young at 17
Then if Brittain sucks we can trade Young to whoever we want. If Brittain does do well, we can delay the Young trade for a week (this means we'll miss out on Milford/Twal/McInnes/someone)
Luckily Souths play first up, so we'll have an idea of our options, but we don't want to try running a poll an hour before kickoff so just getting some ideas now
Unluckily Souths play first up, so if Cook plays and Brittain misses out, we can't use him as a loop enabler for other players.