I'll just throw in general tidbits.
-Pika camps Zelda. Zelda cannot camp back simply because Din's is a terrible projectile. Her reflector is useless against nearly any spammable projectile, and thunderjolts are no exception. This is pretty standard, since Naryu's is terrible for reflecting anything but those random Charge Shots or Aura Spheres. (since those aren't spammable projectiles to being with)
-Why is getting camped bad? Simple. Zelda has a poor approach, and when she's camped, she has to approach. Approaching from the air with Zelda is suicide against nearly any character, and it's difficult to even hit someone as small as Pikachu from tg of ithe air with kicks. If you approach from the air, all Pikachu has to do is shield and punish. In fact, every character can do this. That's how poor Zelda's aerial approach is. She has no aerial with significant range and all of her aerials put her in a position to be punished if she uses them as an approach.
-Zelda fares a little better when approaching from the ground, but it's still terrible for her. What can she do? Running Usmash? Dash attack? Both of those are easily punished OoS, much like all of Zelda's moveset that isn't her Fsmash. Her grabs are also a terrible approach, since they're so slow. They're the slowest non-tether grabs in the game, and the range that they have doesn't make up for their terrible speed. We've actually been able to spot dodge Zelda's grabs just on reaction, since that's how slow they are. Provided your character has a good spot dodge, like Pika, this isn't difficult once you get the hang of it.
-Oh, and if Zelda gets knocked into the air, she's at the mercy of Pika by that point. Zelda has no defense against an aerial barrage, since her aerials are pretty terrible at intercepting attacks. Especially since she has that huge blind spot below her. This is a universal disadvantage that every character can take advantage of, not just Pika. However, the Pika's speed and quick attacks makes it easy for him to capitalize on an airborne Zelda.
-Pikachu may not have the strongest attacks in the game, but Zelda is light. That makes it easy for Pika to kill her. Especially since he can rack up damage safely and easily against her. Plus, Zelda is gimptastic. Her recovery is terrible, and Pika is quick enough to exploit that.
-In short, Pika smacks Zelda around in the air. On the ground, he camps her and punishes her too well. He also edgeguards and gimps her decently. (but who doesn't? lol)
EDIT: @MrEh: Btw, that chart design is amazing. I like.
Thanks. I'm still working on it. ^^