According to co-creater Burnie Burns, Caboose was given the old style Spartan helmet from Halo: Combat Evolved (2001) as a way to differentiate Caboose from Church due to their armor colors being too similar. The creaters have also commented that due to Caboose's personality, the more simplistic helmet design was a better fit for his character.
The different windows that Simmons browses through (using Alt+Tab), while in Central Command, are as follows: "My Terminal", "Classified Docs and Dessert Recipes...", Top Secret Conspiracy Plans.doc", "Spartan Hotmail - Login", and "Cortana_Nude_fake1.psd".