The answers are possible, NO and NO.
A good opening will give your child a good start. But for any parents who are reading this FAQs, I can confidently say that your child wins or loses a game by tactics, 100% of the time. Opening lines are not critical at all. For anyone under 1500, do NOT bother studying opening at all. Remember the opening principles and use your common sense. That's enough to survive any opening.
If you want to kill your child's interest in chess, you can force him/her to memorize opening lines. I can bet in a month s/he will completely give up on chess, declaring that chess is so boring. Human is not a machine. Our memory works best when we are interested. Good players always remember many great positions. But this memory comes from years of study, practice and analysis, not from a few stressful memorization sessions.
Opening traps may help him win games quickly once or twice, but they actually do more harm to him. He gets into a bad habit of focusing his study on traps. In chasing a good trap, he will forget opening principles. Most traps require some time to setup, so if his opponent doesn't fall into the trap, most likely he will lose a few tempos. The rest of his game will be very depressing because of the late development. I have a student who always wants to setup checkmate on f7 with his Bishop and Queen. I have to forbid this practice, otherwise he can't learn how to do a normal opening at all.