Clarification on Farsight

In Farsight all Auspex powers, except spirits touch, can be used. No other disciplines can be used.

To Farsight someone, you need familiarity. If someone with Farsight enters telepathy with you, that should be enough for the 9 mental trait test to Farsight them back. If someone in astral manifests before you, that is also enough.

When it comes to Chimestry, illusions can be controlled via Farsight but cannot be changed ie. an illusion of a knight can remove a helm to reveal his face but cannot have a different face than when the illusion was created. Blood cannot be spent through Farsight to create new illusions. New illusions can be created with Astral but the player has to manifest to do so and spend an additional mental trait to do so.

If a person met someone via illusion from Farsight, they would not be able to Farsight the illusionist because all they have met is an illusion. Unless the illusionist somehow manifested in front of them or used a discipline similar to the requirements for summon.

If I farsight a familiar person A, and they are in a room with unfamiliar-to-me person B, am I able to later farsight person B on the basis of having previously encountered person B while farsighting, or do I need to encounter them at least while Astraling or in person in order for them to be my target?