Bringing the subject to what it was supposed to be, winners.
My guesses are:
Boys
U19 - Aamir Atlas Khan (I know Omar did beat him last time in the WJO but Aamir has improved a lot since then.)
U17 - Mohamed El Shorbagy (Getting training from Mr. Barrington after all but hoping that Waqar will cause an upset.)
U15 - Danish Atlas Khan (Asian Junior Champion)
U13 - Nasir Iqbal (Just going with the seeding)
Girls
U19 - Raneem El Weleily (Is there any other choice

)
The rest of the girls categories I would go with the rankings since I don't follow junior squash that much.