The stunted little one will make it mate, no problem, I had a blue mystic and a royal dwarf who started VERY slow, 2 sets of leaves at day 21 and tiny, one morning they showed pistols and literally boomed and finally have away 17 and 14g in the end. I still don't know what went wrong with these two, as they got same mix, feeding and conditions as others... Just give them the live and attention they deserve 
