It's somewhat spoilery. Keep listening to the Evelyn audios in order, and you'll find out how she ends up connected to the seventh Doctor.
I don't think there are any post-"Survival" audios where the Master is in "Cat Mode." There are, however, a couple where his Trakenite body has degenerated into a corpse-like state, allowing Geoffrey Beevers to return in the role. Those are the seventh Doctor stories Dust Breeding
. The first is all right but nothing earth-shattering; the second is very spooky even if its mythic elements don't quite work. The Beevers Master also reappears in the first series of Fourth Doctor Adventures.