The stadium is not exactly in Lille but in Villeneuve d'Ascq which is next to.
Hereafter you can find 3 clubs which are quite near the stadium, with kids who can see the stadium everyday, but maybe they can't go to see a game.
US Ascq
secretariat.usascq@orange.fr
VAM (Villeneuve d'Ascq Metropole)
vam.football@gmail.com
Etoile Club (étoile means star), club from the nearest village (in fact it's even closer than VAM's ground)
secretaire@ecactg.fr
US Ascq is a good team, they are competitors. Etoile Club is the weakest, it's more like "pleasure football".
An other solution is a LOSC (Lille !) fanclub especially for kids (8-18 yr), which try to teach fairplay, respect,....to these youg supporters. They already have their year ticket for Ligue 1, so maybe they already have bought their ticket for UEFA. They are named "Doggies" (the dog is the mascot for Lille, and the dogs is the nickname of the players)
association@doggies.fr
Maybe you should decide together who you choose, because if there is only 2 or 3 tickets for a club, it could be quite difficult and unfair for the president of the club to decide which kids he gives tickets. However it seems you have bought lots of tickets, so maybe you can please several clubs.