In each entry, the first and third clues lead to occupations, while the middle clue leads to a single letter. The letter can be placed somewhere in the first word to form the final one.

"Starbuck, e.g." + "type of shirt" = "HO scale model builder"
leads to

first occupation letter second occupation
gourmet's best friend + first person (not Adam) = type of executive officer
helper + "Pop Muzik" recording artist = housekeeper
hip-hop artist + symbol on dead end sign = dealer in pelts
cafeteria worker + opp. dir. fr. L = scofflaw
someone often in over his head + not D nor I, politically = raceway V.I.P.
errand runner + type of train or wing = hole filler, hopefully
installer of brick or carpet + presidential nickname = suer, sometimes
believer in flour power + between "P-R-" and "-D-2" = one who stores your bread
doctor-in-training + green vegetable homonym = top dog