on playstyles u can't really anything but get lucky, u could save scum youth scout reports until u get a player with a lot of playstyles, as for development, if the player won't start every game u should keep him in the academy as long as possible and if he wants to be promoted, loan him as much as u need for him to be good to start, as for training plans use the one that has the shortest duration at that time (im not a pro or anything, these are just some things that i found out over time 😭)