It is always better to start with the opposite training. So big players should start with guard-training and Guards with big man training, in case you want to build player that needs from both.
Your superstar is just 18, he can be what ever you want to train him, the skills are quiet balanced. But from his size, he is more a PF than a SF. So you can expect, that training his outside skills will take some time. And this is where the other two trainees can participate.
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