I just skimmed through all of the non Starship elite professions, and none of them require professional abilities. Also, none of them have an alternate ability that would exempt a character from the other prerequisites of that elite profession.
All of them, however, do require an edge or flaw (I'm guessing that the "notoriety trait" requirement for Assassin is supposed to be "Infamy"?), as well as certain skills and/or minimum Reactions.
Hope that answers your question.
Davy Jones
"Frightened? My dear, you are looking at a man who has laughed in the face of death, sneered at doom, and chuckled at catastrophe! I was petrified."
-- The Wizard of Oz