First of all, know your match-ups better. When a Fox tries to up-b from under the level you always drop a spring on him. You can maybe dair if you think you have enough time. But trying to get next to him and doing whatever the hell it was you were doing was a bad idea.
Also, stop trying to bair Fox so much when you're chasing him vertically. That's a lot more difficult than simply uairing.
I liked how you did in the second video right after you took his first stock up until the point where he KO'd you. I think you were flowing pretty well and making yourself invulnerable while getting a quick +40% on him. After that though the match kinda sucked overall...
General note: grab more. You seem to like spin dashing a lot which is fine since your opponent didn't really have an answer for it, but grabbing a lot more would have helped you I think.