That means you will be able to Awaken your Judicator only as a Dual Class ("second main") and can not participate with it in the Olympiad. For further details see this article: http://lineage2.playforum.net/news/lin2hot/id/1045226
"Through Stone of Destiny, players can freely choose any class to be awakened during awakening process. When GoD launches, all 76 and above players will receive 1 Stone of Destiny"
Doesn't that mean that I could take my Kamael Soul Hound and transfer to an Enchanter as long as she is above lvl76?
Kamael may awaken their Main to Enchanter with that stone, but, if I got the whole restriction thing right, you won't be able to Dual-Class your Judicator Sub, if you wanted to.
So your Soul Breaker may Awake as anything except Enchanter (provided you hit level 76 prior GoD) and you may Dual-Class your Judicator Sub in order to awake it to Enchanter.
Or you may awake your Soul Breaker as Enchanter (and it will get Hierophant's Skills once Awakened) and then you can't Dual-Class Judicator.
Either way, you can Dual-Class your Trickster and Awake it to Yul Archer or Dual-Class your Doombringer and Awake it to Tyr Warrior, provided you didn't awake your Main-Class to one of them.
You main and you Dual can't be the same awakened class.
Kamaels main/sub in combi with awakening & dual class is still very complicated as it was bugged still in Korea at GoD Go Live there and if I understood it right only recently got fixed..