Is Francesca Evil (Major Plot Hole IMO)?

I was thinking the other day, after having watched Ghost Ship a week or so ago and still going over it all in my mind, it seems so weird to me how Francesca and the other conspirators had no problems with everyone else dying on the ship. Francesca in particular I can't work out, because I think there was a note from her in dead Katie's room inviting Katie to join her (and therefore save Katie from being outside on the stage when the wire incident happens), which suggests that Francesca obviously had people onboard who she cared about. With that in mind how could she be ok with literally everyone else dying except her and Jack?

I understand how in the DVD extra she claims to love money above all else, and boasts about manipulating men so easily, yeah yeah I get that, but she just doesn't seem like a total psychopath to me. Loving money and male attention does not automatically equate to being ok with seeing your shipmates all murdered! During the voyage everyone is stuck together on the same ship, so inevitably friendships and bonds would develop over time, so it just seems a bit unreal that suddenly she is ok with all her shipmates dying just to get her hands on some gold which she would have to smuggle onto land, explain to the authorities etc.

Also at the beginning of the film she is performing with other people on the stage with her. So presumably these other musicians are part of her ensemble or what have you. So when everyone started collapsing in the ballroom from being poisoned, presumably Francesca rushed off stage and down to the pool where people were being executed, as we see her there in that scene. What makes no sense to me is what happened to the people she performs on stage with every night, did she just cold bloodedly murder them? And how would she be completely ok with being part of a plot that would see them and other people close to her on the ship get murdered?? Even if she didn't do the deed of killing the other people on stage herself, she would still have known they would die, and that Katie would die too, so in order to have no issues with that surely she must either be a complete psychopath (which doesn't fit with her character really that well at all) or completely mentally compromised by Jack in some way.

The only possible explanation that would make sense to me is that Jack, being an agent of the devil, has the ability to literally warp and twist people's minds to bring out the worst of their repressed desires, greed etc.