Note, Interrogator Chaplains are not the DA chaplains as a whole. They are the most experienced and trusted among them, knowing nearly every secret of the Dark Angels. They also hold the Crux Terminatus. Dark Angels still maintain the normal Chaplain, they just have another rank above that. And as for Chaplains as a whole, aside from successor chapters, their are only two chapters to call their Chaplains different things. Space Wolves with Wolf Priests(Rune are the Librarians), and Blood Angels with the Reclusiarch.