I see that you picked up a Greek player to train as a PG. I would train him plus your 18 and 19 year old. True, the other two have lowish potential, but you can still train a star player for close to 4 seasons, even if you are primarily training 1 position. They are good stop-gaps until you have the cash to pick up better trainees.
On the other hand, if you can find another 18 yr old like the Greek guy you picked up, go for it.
Run of the Mill Canadian Manager