I don't think you should waste time on any of those players. As suggested earlier can you find a good trainee for a small sum.
I could not even get $1000 for my rather poor draft pick, still I would much rather train him then your candidates. And I am surely not advising you to buy my player. My point is only that you can for very small money buy something better to train. Your 24 year old players can surely benefit from the training he already has god so no reason to kick him out or sell him in my opinion but you train im too slowly to be worth it and he also has too poor rebounding for inside training and too poor jump range to be guard or small forward.
My player just an illustrative example on a player that in my opinion is better but still not someone I recommend you to train as you can find better players for a cheap sum.
Weekly salary: $ 2 525
Role: draws a paycheck
(BuzzerBeta)
DMI: 8400
Age: 18
Height: 6'8" / 203 cm
Potential: star
Game Shape: respectable
Jump Shot: average Jump Range: average
Outside Def.: mediocre Handling: pitiful
Driving: pitiful Passing: respectable
Inside Shot: respectable Inside Def.: mediocre
Rebounding: awful Shot Blocking: average
Stamina: inept ↑ Free Throw: average