I would pick the following guys from that extended bench:
Mitchell (confirmed)
Scrimshaw
Mackenzie
Meek
Sub: Maginness
Emergency: Bramble, Long, Lynch
They have named Meek and Lynch who are both rucks so I would assume 1 is a backup to Reeves and would likely play.
Scrimshaw would be likely of the 8 and that means 1 of Mackenzie or Maginness is likely the sub imo.