Logan confirmed this in an interview I think - "Vanessa walks away from this battle in what looks to be a victory. Is this the end of Lucifer or is it another setback?

SO. How about that great rap battle of Verbis Diablo between Eva Green and Eva Green, everyone?

I don't think she is though? I think she's very much still in the same position she was (she is the reincarnation of Amunet, so by default she will always be possessed/the host of demonic presences); John Logan mentioned that she won a battle here with the Devil but not a war; and at the great cost of losing her faith…

But didn't Lilith commit adultery with Satan? I thought that was Amunet/Vanessa's role…hmmmmmm

As Vanessa very aptly said this week, no person in this room [series] is above guilt; they all are morally grey creatures, having performed some kind of terrible, evil acts, some more than others. Caliban, Frankenstein, and Lily have all had their monster sides but they are human too, desperately seeking to better…

I think that's less of being a Nightcomer and just more of her choosing whether to be a monster and using her powers for her own selfish benefit (as she did when she struck down Mr. Poole with the Verbis Diablo); it all ties back to that eternal struggle of Vanessa trying to reach personal happiness but having to…

Yeah, this is what I got as well. Kind of bouncing off @JeffSmith:disqus, she's innately got powers (being a medium and channeling spirits) but she also is the reincarnation of Amunet, who is needed by the Devil/Dracula to take over Heaven and create the Apocalypse. In order for that to happen however, she has to…