Here's what I think about these two -
I think they are Dee's Elder(s).
I've never really trusted the witch from the get go, and the Dark Elder's plan is to release the monsters on Alcatraz and the other holding areas at the same time, let them run amok for a while, and then come to the rescue of the humani, get on their good graces, then enslave them. So I think that this is what they need Mars for, they want him to be the Savior of the humani after they release the monsters.
Osiris and Isis need Dora to release the curse she put on him.
So I still don't really know what to think about Dora, as far as who's side she's on. Osiris and Isis could be pressuring her in some way to release the curse on Mars, or she could be working for them and against Flamel, and, as I said before, I haven't trusted her very much at all since the start.