Cool, Dodger. The more Kirby videos, the better. ^_^
Edit:
First video - Kirby's tech chase is pretty slow. If you can't get to your opponent in time for another grab after a d-throw, try using a d-smash or hammer. If they sidestep, they can still get caught afterward. If they roll away instead, you'll still miss, but at least you won't be punished like when you miss a grab. And if they don't tech after a d-throw, hit them! U-tilts or jab work well in that situation. If you didn't expect them to not tech, then at least get your shield up. If they try to hit you, you'll have your shield up for defense, and if they just stand up without an attack you can still jump out of shield or shield-grab them in time. The worse thing they can do in that situation is roll away from you, but even then you can slide out of your shield and go after them.
Second video - why did you SD two of your stock? Was it a crew battle, or handicap, or what? And you should avoid using D-throw against Samus. All she has to do is n-air you after the throw before Kirby can get out of his lag. This was sort of an odd match because of the stock and all, so that's all I have to say.
Third video - okay, I guess this must be a crew battle kind of thing since Ganondorf jumped off a stock in this video too. One thing you shouldn't do is d-tilt when your opponent is out of range. They can come in and hit you in your lag, as I saw happen in this video. Ganon dash danced and you stuck out your foot and then he went for a Gerudo Punch. Normally you would have crouch canceled that and could counter attack, but being lagged from the d-tilt meant you got launched into the air instead. So, just remember, the d-tilt strike rather quickly, you can afford to wait for someone to really come within reach. Aside from that, it's a pretty safe attack. Oh, and one more thing. When you jumped up to u-air him from under the left-side platform, he put up his shield and was knocked off. Use Kirby's slow air movement in times like these to follow his descent and hit with a second aerial while he's tumbling. Iif he hadn't put up a shield, he probably would have been hit, but he did, so you have to already know what's going to happen next and prepare for it.
Fourth video - Fox is going to be faster and stronger than Kirby, so you just have to know the matchup really well. This way you'll know how to respond to Fox's fast SHFFLs, Shine Spikes, and other evil tricks. Against this Fox, it shouldn't have been too hard to see his attacks coming... he didn't even seem to know how to SHL effectively. Stay just out of his (Short Hop to N-air) range, and you'll be able to dash or slide away from him and move in for a counter attack. The counter attack varies depending on your distancing and time given, but you can go for D-tilt, F-tilt, B-air, F-air, and even things like Hammer and Final Cutter.
When recovering, either go over his head, return level to the stage's ledge, or hug the wall. If you go over his head, he'd just love to u-air you so watch out for that. Returning level to the ledge is a tactic to use because at that trajectory it's harder for Fox to get a quick shine spike (until you reach right next to the ledge at which point you could always airdodge or hit him first). To shine spike you away from the ledge he'd either have to jump at you from above, which telegraphs his attack, or drop down and then jump up for a shine spike - which telegraphs his attack, and also puts him in a position to be hit without jumps.
If you're recovering from below, you'll want to hug the stage as you jump up because he really can't hit you with anything except a shine spike, or something odd like a dropping b-air). Either way you'll be close enough to the stage to see it coming and wall-tech it. Use the Final Cutter before he goes for the hit so that you won't Air Dodge accidentally before he hits you. You can also try to go for a quick u-air when he drops down after you, but woe to you if you miss (unless you u-air and go for a tech at the same time ^__^).