I must say that from a lore- and gameplay-perspective, I don't mind how it is currently, since Tower Guard, Citadel Guard and Fountain Guard are all the same and in-game their abilities fit to the roles they have been assigned.
From a visual standpoint however, I do agree that giving the heroic unit the movie's "Fountain Guard" look (I found a fountain guard model in the worldbuilder, but it's unfinished) and giving the current Citadel Guard model to the elite unit would look better overall.
The names could stay the same or be changed, I wouldn't mind in either case.
Signed,
The Only True Witchking