It's mainly to be the head of operations, the manager's right-hand man for talent spotting and recruitment. Not necessarily to do with attributes specifically as the core ones needed (Adaptability, Determination, JPA, JPP) are all needed. Perhaps Motivation, or one more Mental attribute but other than that there are no differences. 13/14 the base minimum normally, 11/12 for lower league.
As for Head of Youth Development I would suggest a high JPP attribute as he oversees the youth academy at the club and potentially scouts out local talent who may be potential targets. High Determination, Motivation, Discipline and Working With Youngsters are required to be able 13/14, depending on who you are, 11/12 when in lower leagues. Again, no real specific attribute changes, but rather how high the attributes are.