I have been looking around to find this as well, but I've found only an explanation about the titan logo, which is: Six Fronts was one of the earliest battles fought by the City. Four orders of Titans protected the newly constructed walls of the City against six enemy approaches, and not a single front faltered.[1] Some veterans of the battle believed that the City failed to take the initiative to reclaim lost ground.[2] Six Fronts is symbolized by the Titan insignia: A hexagon (representing the six fronts) divided into four pieces (representing the two larger and two smaller orders that fought in battle). source: http://www.destinypedia.com/Six_Fronts If you find something about the Hunter and Warlock, please reply it :)

I believe warlocks is "Rune of the disciple"

The emblems you get are called: Warlock: Rune Of The Disciple Hunter: Aspect Of Blood Titan: Officers Crest

I believe titans is the six fronts. It represents the four titan orders that held back the darkness during the pilgrimage. The two largest orders held the two larger waves while thetwo smaller groups split and held smaller waves creating six place the engaged and held back the darkness either for the pilgrimage and/ or the walls construction. As for hunter and warlock i do not know i havent looked into their lore much

Aspect of blood is the hunter emblem