For the quest to kill five Cuberials, the client's name is "Uni Sound-alike". This would refer to Sayaka Miki from Puella Magi Madoka Magica, since Uni and Sayaka have the same Japanese voice actress (Eri Kitamura) and the same English-dub voice actress (Sarah Williams).
One of the DLC scenes with MAGES. has her repeatedly refer to Noire as "Assistant", to which she strongly objects. This is the same case for Makise Kurisu of Steins;Gate, with who Noire shares a seiyuu.
No Export for You: Only applies to MSX DLC for the North American version of the game. The main game itself is not an example.