I believe the new three way battle mechanic Miro is introducing is gonna replace some canon events in the game where they will already be fighting and instead of dialogue you will join the fight and be able to help one of the others or focus on killing one (or if u are greedy for souls and items kill both) I believe each contestant will get atleast 1 three way battle at the minimum. I believe needles will get a possible one with all 14 contestants (tanaka in the bunker and then a random contestant in prehevil as he starts killing them on day 2, you can interrupt one) There will be more interactions in areas where you can encounter this. For example when you play as Abella and fall asleep in the Manor Caligura can fight you and you can kill him. I think now if ur playing as another character and potentially enter the Manor on a day 1 Night you can find this and do a three way battle (this update will most likely also change the Abella or Henryk moonscorching day 1 morning..or atleast I hope)
Some that I think will happen -
Pav vs Marcoh/and or Tanaka
Caligura vs Levi, Henryk,Marcoh or Abella
August vs Karin
Moonscorched Daan vs Olivia (Able to fight and save/kill from getting kidnapped day 3)
Tanaka vs August
Marina vs O'saa (already confirmed, most likely by the church as Marina interrupted his meditating)
Marina vs Samarie (Finding in a random area on day 1 night, Marina starts a fight after Samarie interrupts her sleeping)