Three of Winston's thugs have the last names Schmeichel, Sheringham and Solskjaer. This is a reference to the goalkeeper and goal scorers on Manchester United's 1999 U.E.F.A. Champions League winning team. The director is a Man. U fan.
In the scene after Milo leaves Building 21 the first time, he's standing outside under the shadow of the mouse satellite dish. The shadow from the satellite dish is cast to the right of the screen, while Milo's shadow is cast to the left. This could only happen with two light sources, and even then, there would be two shadows.
Winston uses IP addresses in the private Class A net 10. This can be accepted as the Internet equivalent of a "555" telephone number. Because of schedule pressure and other plot points, they are indeed likely to be using a largely standard protocol, and not a purely proprietary one.