Maybe add a jester like character, called commander, if they all die then the ship called traitor and the imposter win. You could have it as a commander task will be used one place and a wire or something is shown where the visual will happen maybe in a room alone, a couple away from the task, so you have to trust that the person there with the commander is doing the task and the person at the visual is telling the truth making it so the imposter could easily lie about if groups arent played right.
Interesting idea, commander, could also be changed to something else depending on maps, but- maybe it should be more of, they have to survive to the end, yeah, then do a task, you also said that... BUT, they're announced at the beginning of the game, as the crew of your... whatever depending on the map would know who was leading them, that could also be a nice replacement for a detective. But it should be in a seperate "party mode" with potentially different roles, but only a few, one i just thought of was the "Coordinator" being an imposer who can see the location of other imposters, any maybeeee, place a tracker on one crew member, a subtle animation could accompany it