Nathan Fillion and Alan Tudyk starred together in Firefly (2002), Serenity (2005), and Con Man (2015).
Jackson West's idea of predicting crime is the center point of the TV series Person of Interest (2011) which features one of the series' guest stars, Sarah Shahi.
Nathan Fillion and Adam Busch both appeared in the seventh and final season of Buffy the Vampire Slayer (1997).
Lucy gets frustrated with Jackson having used all the milk, but two episodes earlier she told her mother that there was no milk in her fridge because she's lactose intolerant (with Jackson also living there at the time, that would indicate he didn't use milk either). Nothing about the jug of milk indicates it's anything other than regular cow's milk.