I don't expect it to be uniform. It is more likely to be Gaussian with the peak between 2 and 3 -- extremely weak and extremely good players have to be more rare.
It is definitely not Gaussian. It is much more likely that the individual skills are Gaussian and independent. It's just easier to do it that way, and produces an OK mix of combinations of skills.
I'm not sure I would even expect it to be Gaussian (or if it were we are seeing the players that are at least 1+ sd. Remember that we are looking at the top 48 of perhaps several 100 players. Most of the rest are going to be getting their college degree (sadly too many won't graduate) rather than having a professional Buzzer Beater career.
Star rating vs. letter grade could be a whole pile of different things. The star rating might refer to the overall skill level, while the letter grade refers to the 'in-position' skills. Or it can be top 4 skills (stars) and top 8 skills (letters). Or they might even include height, as it affects the way skills will progress with training.
I am a bit ticked that I didn't record properly the letter grades of the guys I picked last season: my first and second rounders were 5*, though I can't recall the letters for the life of me.
As far as I remember, there have always been more 5's than 4's and 4's and relatively few 2's and 1's.
I think I actually tended to move 3's below the unknowns, figuring that the unknowns had much greater chance of being a 4 or 5 than a 1 or 2.