Aww I was hoping to not get revealed just yet. In order to gather information, I tried creating two alliances, splitting the players in half. Additionally, if everyone participated, we would increase our chances of killing the possessed, as killing multiple people at once is the only way to do it aside from killing both cultists first.
Group 1
: Ryli, Fippe94, Fabian771, theelkspeaks, 1011686
Group 2
UTAlan, Aves, DoubleCapitals, Dawn to dusk, Linkcat, Lunaris
The group that helped kill dawn seemed to all be on board with the plan, while the group that I told to kill theelkspeaks did nothing. There are a few possible conclusions. The cultists could both be in the same group. If that is group 1, they were fine with killing dawn. If group 2, they didn't want to kill elk. If the cultists are in both groups, the likelihood of elk being a cultists is slightly up, but I think the cultists would have swapped him from being possessed if they knew he was being targeted by an instakill strat. Also, I did reveal this plan to Linkcat and he seemed to think that due to the willingness of group 1, it is more likely that that group has 2 cultists. Or Linkcat could be a cultists.
Anyway, now that the plan is known, we need a new one. For starters, taking everyone down to 60 hp may be a good choice. The only way to be easily killed is by the possessed with at least one cultist or a 4 player group (because stuns). This will mean we can split up teams even further, increasing our chances that the cultists or possessed have no knowledge on if one of them is being targeted and our likelihood of killing the possessed instantly.
Let me know if there is any interest in this plan. If there is, we can create a plan to get everyone to 60 hp then split groups up randomly. Once groups are formed, I think that it is in the regular players best interest to go with the plan, and the cultists/possessed players best interest to not. So anyone not helping is more likely to be on the cultist/possessed team.