There is probably a way to actually work this out from known information, but I'm not at that point yet. It is still plausible that 3 players could be the imp, but in increasing likelihood:

1 - Manc, obviously not, I assume there is no mechanic whereby that stunt could have worked, he must be the slayer
2 - Baz, I suppose he could, as a bad guy, have set-up some elaborate no kill on night 1 with the imp being poisoned and then 'killing' him to make his soldier bluff stick, however, if you were going for this you would do it with the actual imp wouldn't you, but Baz must have been the Scarlett Woman in that set-up which would be levels of chicanery too great for me. Well done if so. Having the monk protect him just adds further levels of wtf to the scenario.
3 - Jimmy, I have been suspicious of Jimmy through the game. What Mahow says about his spreading his role about the town and not dying has merit. I suppose perhaps the imp could have been targeting him and other people have died, or at least they tried once before stumbling upon me. It would have been impossible to deactivate his power and poison me on the same night, I believe. Me being vocally suspicious of him to potential wrong'uns would have been cause to keep him alive.
4 - Mahow, ah Mahow. When I said 2% above I was making reference to doubts I had as to his veracity that I discussed with him when he and P_3 seemed to have somewhat interchangeable levels of info on each other from what they had told me [P_3 declared a role to me whilst Mahow said he only hinted, then later in the same conversation he made mention of P_3 being the investigator - I had probably given him something to work with in terms of deduction but it struck me at the time] - we obviously got past that point. Anyway. Mahow says he's the virgin. A claim that is in theory testable. Pleb tested it and lived. OK. Pleb was in the frame as a bad guy and the way he did the check looked exactly like the way I did it last time round, taking it for the team once my number was up. But Pleb being bad presupposes a number of outset facts which do not tally. Pepe said he was the librarian and saw one of Thommo or P_3 as the saint. As far as we know there are no outsiders on play [maybe this is trusting Mahow too much but he hasn't been challenged on this by any games masters so I have to believe it]. P_3 obviously wasn't the saint as the game would be over. Thommo said he was the monk. As a lie that makes no sense. So Pepe's info was bad, or he's just trolled the town for lols. So, with Pepe having bad info we have P_3 and his investigator role. His information was that one of Manc or Pleb was the Scarlett Woman. This must also be wrong as the game would have ended with Manc's slayer shot on Boydy. P_3's information being deliberately wrong is far more plausible. I read Pleb as the poisoner. I went through many scenarios in my mind as to how that might have happened. I knew I must have been poisoned as it made no sense as a ploy from the bad guys to fit up one of their own, but lie about their role. However, at the same time, I convinced myself of a somewhat elaborate scheme that necessitated me being told he was a bad guy, but it still be bad info. In hindsight I was looking for this to stick with my trust in Mahow's role. If Pleb was good, then short of some otherwordly levels of poisoning skill, he should have died with his Mahow nomination. That he didn't, and then slunk off into the shadows never to be seen again [further classic bad guy behaviour] can only mean that Mahow was lying about his role, and if he was lying, well, what for?