1st match- I Didn't see one grab. Grabs are key for pika since Ganon has a dthrow chaingrab that inescapable up to 37%. Also try to fully space your aerials (using only the tip of Ganon's fist) for optimum priority and preventing your opponent from getting inside. And like RIP said, don't get too close to the edge when applying edge pressure, and I'd recommend having your back to the ledge so you can bair (massive priority, range, and long lasting hitbox) or reverse uair (covers a broad range of pika's recovery options, including sweetspots, and semi-spikes).
2nd match- Ease up on the smash attacks unless you know they'll hit, and drop utilt altogether. Utilt is really only applicable for edgeguarding other Ganons, Falcons, sometimes Sheik, and a few others if you're really good at timing it. Be careful going offstage to edgeguard, you could wind up getting gimped or edgehogged. Unless you absolutely know you're going to connect (like if your opponents options are limited), it's better to stay on stage and tilt or aerial (keep in mind reverse uair hits sweetspotters and bair just *****). If pika is relatively far from the stage, you can hang on the ledge and force him to land with his up-b landing lag. From there you can ledgehop/ledgedash + grab, or aerial if they're on a platform.
You played a little better in the 3rd and 4th matches. Remember to DI away from pika at low% so you won't get combo'd as much.
