Would focus on the greek, he's a bit tall for SF, but a bit short for a big, he could be a short PF. or a hybrid inside build SF with that height. (remember shorter guys train outside skills faster, tall train inside faster - that's why 6'6 is magic spot for SF)
good potential in superstar too, i'd focus on your greek guy, with a good season of pops he should make it to u21, i think he's about a fringe potential u21 player atm. Well, that's based on the USA/Romania systems, i dont know the quality of greek u21 SFs.
probably wont get a mil now, as a 21 year old, esp if he's on the roster yes, but that doesnt help the u21s lol, once you get all his skills to around 10-12 he'll be worth over a mil easy.
i want to start training a SF next season myself...