I watched the first video and my main gripe is how can someone let MK use the same short hop strategy two matches in a row. He used short hops to pick up, attack, and catch bananas. After the first 2 or 3 times, a counter strategy should have be developed. Maybe feign a banana pick up and fair to predict his short hop, upsmash, or even scrub rolling. The point isn't even to break him, he might have had other ways of dealing with bananas. You want him to constantly switch up his style, not kill you with the same tactic. It looked like rock-papers-scissors and MK using a bunch of rock, 2 papers (shuttle loops) and then back to rock.
Our recovery isn't that good people. There are two important things Diddys have to learn. The timing of invincibility frames from ledge grabbing. The other thing, knowing how to recover ON STAGE from all angles. Getting on stage should be priority one. I haven't seen a player do up+b on the stage and fall to his death from going through the stage, but I have seen many Diddy's hit the side of the stage because they chose the ledge instead of the stage to save percent from being punished.