replicating it is extremely easy. Applying it in a 1v1 fight is what i'm trying to figure out how to do.
Here's the thing. The pikmin doesnt work as a sheild. The pikmin is BARELY in front of olimar, and if it's not spaced right, olimar will be hit as well. So for one, it's entirely difficult to space. Also, if the attack isnt going to hit you anyways, it'd be better to just take advantage of your opponent getting outspaced.
So I tried a few thing. These WOULD be the most practical ways to apply this. Pikachu's skull bash stops when hitting anything, including pikmin, so charging a FSmash WILL sheild olimar. However, unless the pikachu DOESNT charge the skull bash it'll kill the pikmin. And an uncharged skull bash will kill everything but a purple pikmin. however, testing it more, I couldnt get the pikmin to land right to be released from the right position to hit pikachu after his lag. Ike and Luigi both have an attack that work the same way, but they both will hit olimar as well as the pikmin (Luigi's actually doesnt hit the pikmin lol).
Here's what I want to do, but i'm gonna need a second player that knows how to play peach well. I'll be at a smashfest this weekend so i'll have rowan help me out. I want to see if Peach's Dair can be made to hit a charged pikmin before it hits olimar. This will cause the pikmin to be boosted into the air, come back and hit peach. However, olimar WILL get hit by the DAir most likely, so it'll probably be a trade but this would still be interesting.
i cant think of anywhere else to apply this. And about whether this is a Glitch or AT or whatever... it's not either. It's not an AT until we can apply it. It's a part of the physics of pikmin mechanics. Until we figure out something dramatic, it wont be more than that.