Jehudi signifies a Jew and Cushi an Ethiopian, but it seems reasonable to conclude that they are genuine, proper names.
Related Commentaries of Jeremiah 36:14
Jeremiah 36:14
14 Therefore all the princes sent Jehudi the son of Nethaniah, the son of Shelemiah, the son of Cushi, unto Baruch, saying, Take in thine hand the roll wherein thou hast read in the ears of the people, and come. So Baruch the son of Neriah took the roll in his hand, and came unto them.