nope,I never ditch my starter thought the entire journey before but after I beat the game well...you can guess
let's me give you a hint:leveling up pokemon and breeding need room so
1.You can get Riolu by doing a little sidequest in amatrine but after you beat Blake(I guess)
2.I don't think there's a EV reseter in Reborn or maybe there is but I just don't know...sorry
Edit:I forgot about the berry...- -