Here is the summary. My English is not that good. Hope someone can correct me :) :
1. reputation of your club. The only way to improve it is win and win.
2. youth rating: how good a country produces young players. We cannot control this without changing pre-game editor.
3. Head of Youth development. The reputation of him is very important. All the higtlighted attributes seem important. Working with youngsters helps with deveolping your young players. Tactical style and preferred formation will influence which player they bring in. The world knowledge of him will also have some impacts.
4. Youth recruitment and junior coaching, which are the last two rows in the facilities. Recruitment is just a budget, which will directly affect whether high-potential players come in. Junior coaching is how good your youth coaching are. It will not influence the players you bring in.