I've never heard of Super DJC before. He must be hacking
Even with humanly perfect DJC, I would still consider this ++ for jiggs. Just because it's hard for Jiggs to approach doesn't mean Jiggs must approach. If the Jiggs player is unable to hit the Ness player, Jiggs can just wait on the side, taunt cancel, do a couple of sings, etc. until the Ness player's fingers get tired of DJC spamming. But even with DJC, puff can still hit Ness. If puff just plays aggressive and goes all out on Ness, then yes, puff will get stopped by DJC'd Uairs, and every failed attempt will raise puff's damage, slowly resulting in the loss of stocks. If puff plays puff-like and waits for the best opportunities, then one messed up DJC results in the loss of a stock, a perfectly timed Dair will hit between DJC's, resulting in the loss of a stock, a grab as Ness lands results in the loss of a stock, etc.
Ness, on the other hand, doesn't have much against puff other than longer-ranged attacks. He can't combo puff well, making any mistake results in the loss of a stock, etc. Puff beats ness in every category except for range, but that isn't enough to move the matchup off of ++ in my opinion.
Pika vs Puff: I do agree with --. I played more friendlies with Kefit, and the more we play, the more he learns the matchup and the worse and worse the result for puff. If a good Pika knows the matchup, then it will probably end up -- for puff since pika out-ranges, out-prioritizes, out-maneuvers, and out-***** puff. The only thing puff has for her is her 0-deaths on pika, but a pika that knows the matchup enough will know what to avoid and will just **** puff. Still one of my favourite matchups as puff though...