Oldies such as Aria hold some nostalgia for the rebellious ragtag of Generation One era. Rose tinted glasses of the our more worse times. No matter.
I cannot determine much beyond that Aria seems to be heavily invested on finding Revenant too, I believe they may have been friends back then, so I hold no worry in them terminating her upon discovery. I cannot say if they are capable of maintaining a shut mouth in regards to the Sentinels. I would first gauge on how much they know before exploring such areas.
Aria has some level of competence. As for Kimiko... Not a clue.
I do not know that Freelancer too much, but they're likely invested for similar reasons, that or a business interest. They seem to be a believer of a type of anarchic philosophy, though I do not know them too initimately. I believe they may know about the Sentinels already.
You could always test the waters and send her on some dummy missions.