They're just missing (on a mission, hanging out Elsewhere, etc).
They're completely destroyed.
It's arguable that the Maidens have to be functionally insane to do their jobs. For example, they can't possibly be in one place at a time. They can't care about anything else in the way that they care about their Attribute. So they may not have the same pieces that a sane human consciousness does. For example, Maidens may not be stateful. That said, maybe they're broken up.
They're completely destroyed except for one bit, which is with the PCs.
The PCs have their personality, but no memory or power.
The PCs have baby rebooted tiny Maidens, who cannot do much useful to begin with.
The PCs have inanimate totems of the Maidens, which are useless.
The inanimate totems can be activated to provide some level of utility.
The inanimate totems can be inspired to become living, mildly entertaining animal companions.
The voices of the Maidens echo in the character's heads, principally played by other PCs. For example, Thomas might be playing Nameless Crow and The Voice Of Mercury.
tmack: That's my favorite idea so far (although I would prefer not to get stuck voicing Mercury).
bts: I picked Mercury to demonstrate that you're playing the voice of someone else's Patron. You're certainly not playing a Journeys, so...
tmack: Right, I noticed that, but still, ewww, Journeys. If we wind up going ahead with this plot, I think Nameless Crow might broach the subject of whether the Maiden of Journeys is, strictly speaking, necessary to the long-term strategy of the organization...
AT: Ooh, the Shadowguide mechanic. I always loved it, though I'll admit I was never a great Shadowguide. In order for this to be interesting, I think the Maiden voices need to have some well-defined traits and goals, and they need to be at least somewhat at odds with the characters.