Sorry for the delay, but I got some details related to characters that swap factions and these requirements! If you do a faction change your reputations will switch over but quest completion does not, so if you want to qualify to unlock the kul tiran/zandalari you will need to do the main storyline for that continent and faction.
Note that for the War Campaign aspect, if you got to exalted with 7th Legion/Honorbound then you can just do all the chapters without any delays to gain more reputation.