Over tea and biscuits yesterday afternoon, out in the yard because they're really not getting much sunlight while Keltham is active, Carissa and Maillol worked these out.
The options are:
There is another secret project that can accept second-circle wizards; the girls would have to be screened for suitability, and might not prove suitable, in which case they could pick one of the other options.
They can go to Hell for not longer than five years, shorter if Keltham and Cheliax agree they no longer know any state secrets.
There exists secret and powerful mind control that would render the girls unable to recall any events of the last week, after which they could resume their normal lives; this would be by far the most expensive option to Cheliax, not least because there's no way to avoid the girls knowing it was done to them, and the existence of such capabilities is itself secret.
They can go to the afterlife of an allied god, if they'd rather that than Hell and the allied god promises the same secrecy Hell could provide; the cost of this is hard to estimate, but it seems like maybe the kind of thing Cayden Cailean would agree to.
They can remain on site and get a tutor to teach them some useful and valuable magic, and interact socially with the core project girls; this might be healthy anyway, so the girls can have some friends and romantic partners who aren't their collaborators in a high-stakes project.