Honestly, the
MU isn't as bad as you think. Still mostly in his favor, but his ranged options arent that effective against puff (who can just duck under crash bomb and metal blade gives puff a shield break option and a rest setup). His close range options are fairly easy to bait & Punish as well as long as you mix up your baits.
as well doesn't have an advantage because of his speed, if anything that's a disadvantage as trying to take advantage of that against puff ends with either a rest "counter" or a nair to the face. His advantage comes from throws that can easily kill puff as well as better kill options and frame data.
has far from the best roll in the game, it's a bit in the middle. Nair easily punishes a M2 that rolls a lot. In all honesty, while M2 got a buff with the recent patch, I still place puff as having a very minor advantage against him due to him being about as light as puff but far easier to hit. Shadow Ball is very easy for puff to avoid if you are paying attention to your jump count and watching. His tilts, up air, and bair are his best strengths against puff.
A decent/goood
can mess puff up, I'd say the MU is fairly even though.
is, imo, easy to handle as puff but that might be because I main both. Clay Pigeon and Wild Gunman are both easy to avoid for puff, and nair/fair knock the can away with ease, even airborn(often back into his face). His recovery is also easily gimpable by puff. On top of that, his smashes have a nasty flaw where they can knock puff out of range of the kill hit. The only real threats from the pooch are up air, which is also easy to avoid as long as you have jumps remaining, and up tilt, which you can avoid by just not approaching from above. DH just requires patience and paying attention to animations.