zoning eh? sorry i'm new to the competitive scene so i'm uncertain what that is
A zone, if I am correct, is determined by the range of your attacks. So, if you have a projectile, that also counts as a zone. If you step within that zone, they will attack, whether it be a projectile or a close-combat attack. (depends on how close you are) Be wary when approaching an opponents zone. Using your projectiles from a distance can be considered "zoning" your opponent out, though this shouldn't last very long if you're against a good opponent.
Keep in mind you can shield during a dash, and dash again after the shield.
Link's boomerang really shouldn't be a problem though, LOL. It's pretty decently slow to come out. You're likely going to meet a lot of players like this in the future. Analyze your play, look for your mistakes, and look for things you could do better, like how to approach your opponent, maybe next time you can jump over Pikachu's Neutral B. (Or in Link's case, shield his Boomerang)