The answer to that is 'DEFO', the FO spots will go to outsiders when needed, that is after the current DESO's are moved up to JFO.
My "crystal ball" is telling me the ICadets will stay as SO's for the maximum term of their contract, then be upgraded very slowly. Because after-all they will all be soooo bitter by then that as soon as they make FO and get some time on something larger than a Cessna.....they will be leaving in droves.
However if you are 20 now, you will be a Widebody FO before you are 30, and with 30 more years of flying ahead of you this might just payoff for you? Now if you are 30+......well......ahhhhh
