One problem with the present game state is the fact that we appear to have more information than we actually do. Both Minish and PK were fed by SMS, with SMS presuming their respective and prospective alignments. Naturally, the kind and quality of the information, as well as the implication behind that information, differs according to each case.
The crucial aspect is whether or not we are willing to equate SMS's intrinsic need to lie to protect himself with an actual dual motivation. Which is to say -- if you, as mafia, start the game with a known potential mole in your ranks, are you not in any case required to play in such a way as to minimize the threat? Given that Minish is believably intrinsic to The Jackal's character and motivation, it is comprehensible that the Jackal might re-tool his role to 'suit' Minish's presumed alignment. But at the same time, if the Jackal is meaningfully motivated to protect Minish, or at least not to kill her, then there ought to be some component of his role that explains this careful behavior.
In other words, there ought to be some disjoint. Either they are both dual win condition (potentially with separate motivations for their respective town-scum possibilities), or The Jackal is mafia/dual and Minish is town. It is technically possible that the Jackal is town but trying to conceal his 'true' nature from the mafia side, but this doesn't adequately motivate his tension with Gwen. On the other hand, if the Jackal is strictly mafia, then either he needs to convince Gwen that he is 'good' despite Gwen's own town alignment, or he needs to convince her to turn to the dark side/fall/etc, but again we encounter the 'why?' problem of mafia essentially getting the job done itself. So either the Jackal has some arbitrary weakness of needing to fool one particular actual human in order to win (because otherwise 'being mafia' almost motivates him to jettison his Gwen baggage), or something complex is going on.
In short, for those who want less hedging: SMS probably does have alternate wincons. We must remember that he is compelled, in the context of the mafia chat, to act like mafia, and that the information he provides to the mafia members (e.g. PK) must be consistent with the potential of him being mafia. Likewise, in his discussions with Minish, he must make himself redeemable (and, to some at least minor extent, likely is).