Help with YS stars wanted

[ProPain]

So what do these star ratings mean?

Mr Fredje Hecht,freshly promoted scores 4 stars on midfield but what does this mean skill wise? Same for my forward Wieger van der Wel, 3,5 stars what skill level is this.

Also all skill levels are still at unknown, am I correct in assuming these aren't updated yet? Or will they update only after training or level ups ?

Fredje Hecht seemed a man among boys in that aerial challenge, following Cornelus Zwagerman's corner kick. He rose high to head home, bringing the score to 2 - 3 after 70 minutes of play.

Does this mean Hecht has/might have head specialty?

Questions, questions