Mattie's Headcrack username is Hu-bot97, which is an homage to the original name for synths, Hubot.
The play the synth named Howard (Matthew Tennyson) refers to and was asked to leave is Arthur Miller's "Death of a Salesman."
Both Gemma Chan (Anita) and Naoko Mori (Fiona) have been part of the Doctor Who universe. Gemma as Mia Bennett in the Doctor Who episode The Waters of Mars, and Naoko as Dr Sato in the Doctor Who episode Aliens of London, and also as Toshiko Sato in the Torchwood spinoff.