Don't forget intercom systems which allowed the crew to speak with each other. Most of the "chatter" you hear in movies/newsreels about bombers is actually intercom transmissions. Different from radio, but it had its own communication protocols, and is important to distinguish.
Liaison equipment could also be used to communicate with Air/Sea Rescue should the bomber have to ditch or if its crew saw another aircraft in distress.
By the end of the war, some USAAF and RAF heavy bombers carried Electronic Intelligence and/or Electronic Countermeasures equipment. This equipment would be used to monitor German radio and radar signals and/or to jam them.
In addition to voice communications, much liaison radio comm was via Morse code, usually with messages encoded to prevent the enemy from (easily) deciphering them.
Terms like "red" "blue" or "white" were used to identify squadron elements, with a number typically used to identify the aircraft's position in the flight. IIRC, it was red, white, and blue for three sections, and green if there was a fourth. Occasionally, the squadron commander would be identified just by call sign and a number (e.g., "Black Sheep - 1"). Squadron and/or Group call signs might change, either for security purposes or for other reasons. I've been looking for a good list of unit radio call signs for years, but haven't gotten anything useful. I'm guessing that the information is hidden away in After Action reports in the bowels of the National Archives, and hasn't been published yet.
USAAF radio protocols didn't vary that much from modern military protocols, although the phonetic alphabet was different (Able, Baker, Charlie, Dog . . . vs. Alpha, Bravo, Charlie, Delta . . .) and modern conventions for pronouncing numbers had yet been adopted ("Nine" vs. "Niner," "Five" vs. "Fife").