that's super interesting, it probably makes diddy play safer than usual until figured out
Any knowledge on Custom Villager or Olimar?
Villager's most common customs:
Exploding Balloons. He can explode them by pressing a (or both by pressing a + b) and if he explodes both, he gets shot up. If he chooses to explode both balloons, he can not grab the ledge until he reaches the apex of his jump, so keep that in mind. If you hit a balloon, it will explode and it will hit you. When he grabs the ledge regularly (by not exploding the balloons), the balloons will fly away from the ledge (one in each direction). This means that one balloon will go through the stage. I haven't played Villager myself, so I'm not 100% sure about all of the stages this can happen on. I have yet to see a stage where this doesn't happen. The same rules apply for this balloon (if you hit it, it explodes). I honestly don't have a lot of ideas on how to beat this as Diddy. Sorry :/
Tripping Sapling -> Counter Tree. The sapling trips, and if he waters it, the tree will generate a hitbox whenever hit (by you or Villager) that will not hit Villager. The trip deals 2-3%. The tree counters for mediocre percent, the tree hitbox when cut down is weaker (from what I've been told, the villager I play against doesn't cut it down ever). Avoid the sapling. The trip box isn't too big, so it's not too difficult to avoid. The counter tree is pretty straight forward, too. Don't play near the tree if you don't have to. He can slingshot the tree from afar to hit you with the counter box.
Pushy Lloyd. It's a bigger, multi-hit Lloyd that doesn't go as far. Explodes at the end of the move. The Villager I play against doesn't use this one against me much at all. I doubt Banana will destroy the Lloyd, but I can't confirm that off the top of my head. It may be better to jump over this one and go to a platform instead of just shielding it, as similar to playing against other characters with Multi Hit Projectiles (Robin, Greninja) he can hit you if you're shielding the projectile.
Last of all there is a big pocket that Villager has that is igger than the regular one (someone on the villager boards said 1/4th of FD). This will pick up banana very easily. Be wary of this if you're going for banana combo's. The downside of the custom is that it has less knockback, but Villager can just keep the banana, so he'll probably do that to remove it from your moveset until either of you die.
As soon as I can play this matchup more, I'll have more thoughts, but this is all I have at the moment. I apologize ;_;.
Edit: Olimar:
The only thing I know of Olimar is Sticky Pikmin and Hardy Pikmin. Hardy Pikmin are more difficult to kill, while sticky pikmin stay attached to you longer. Trying to kill/knock off the Pikmin with this combination is pretty much useless (takes far too long if you can get them off at all).
Olimar will generally save his whites to throw at you. If you see a white next in his line up, prepare your shield for that (make sure it's a full shield so the Pikmin can't latch to you through shield). Since the Pikmin stay on you for so long, the more he has on you, the less Pikmin he has to work with.
Hardy Pikmin has a very big delay when plucking pikmin (imagine 1.5x - 2x the lag from Peach Turnip if not more). When new stocks occur, you should be able to prevent him from getting his third Pikmin. If he is EVER in a scenario where he doesn't have Pikmin, do NOT let him get Pikmin. Grab him and juggle him as hard as you can, because he will have no options as long as he can't get to the ground.
Random note with hardy pikmin is that his dash grab is non existing when using them. I've seen it with Blue Pikmin specifically, but I'm talking with my Olimar friend and he says it's consistent with all Pikmin. I'll test it tomorrow to make sure personally.
The only other customs I know of are the down-b that will hit you if any of the recalled pikmin go through you (shield it?) and an up-b custom that makes the recovery height consistent regardless of the amount of pikmin you have (and it's still a pretty good height, just not as stupid).