I think Seagull Joe has the matchup for Ness v. Diddy right. Its probably either 50-50 or 45-55, on account of how well Diddy edge guards Ness and generally outperforms him in neutral. DIddy also has good OOS options so I kind of don't see hi losing in neutral that badly.
Its basically a very stage dependent matchup.
As for Ness v. Wolf...I'm undecided. Wolf's neutral doesn't seem as bad for Ness as Fox/Falco. But I also don't understand why everyone assumes Wolf is top 3 characters in the game. I see him as by far the worst spacie.
He doesn't have the lead in to kill moves like Fox/Falco (jab fsmash/usmash), he doesn't have a comeback mechanic like fox's shine or falco's dair, he has an insane combo game--true, but so do fox/falco with their speed and hit trajectories respectively. His neutral game is definitely not as good as theirs (with a clankeable laser and okay speed, although his laser is much better than it used to be). Finally, his recovery is barely better than Falco's.
His shine being crouch cancellable and also not as safe in conjunction with his aerials as fox/falco means his pressure isn't as guaranteed.
Maybe the full exploration of his energems setups will change my mind as its a pretty potent tool that, when optimized, will be truly terrifying. But you can say the same things about the tool kits Lucario has, or Snake, or any of the other upper mids and high tiers we have been discussing.
Everything here about wolf isnt that accurate, other than cc and asdi down on shine being a thing. His entire kit leads into side b kills, that's both his reliable kill setup and his comeback tool, just like other combo heavy characters have.
while his approaching game isn't as strong as the other spacies (due to the blaster changes), the same blaster changes made his neutral very strong and non commital. He puts out hitboxes that he can convert off of easy, taking free stage control/presence while not commiting to anything but the jump and Waveland. It's flexible movement while putting out a combo starting projectile, and while it's clankable, it being clankable forces a response to the opponent and also clank other peojectiles, most often leaving wolf at advantage because he can just wl forward and use the space he just took from them for almost free.
he doesn't have a good approaching aerial like the other spacies have, because nair is multi hit it has no priority and doesn't trade well. Other than that his neutral game is fantastic.
His pressure is just as good if not better than the other spacies. If they shield the nair, it's guarenteed to be a shine unless thry have a frame 1 up b hitbox (it'll trade) or invincibility on frame 1 of an up b, because nair is -1 on shield due to its landing hitbox. Dair is -3 on shield when done perfectly, so that's not bad at all (fox's dair is -8 iirc). He has the same double shine/shine grab game as the other spacies, but he converts stronger off of grabs than falco does, more reliably than fox does, but like Falco he can still convert off shine grab if the shine hits and grab whiffs. The only thing his pressure lacks is a move other than blaster to really force them to shield you.
Combo wise he is still very very undeveloped, but even there's no reason even at this point in his meta for top players to not take stocks in 1-2 conversions. It's a very very silly combo game that works on the whole cast.
His recovery is also leagues above falcos, no charge time (only 5 frames), good hitbox, side b has 3 angles to choose from for even more mixups. Fox has him beat in sheer distance but in difficulty to edge guard wolf's is on par with fox if not the best out of the spacies.
The difference between wolf and lucario/snake is that he is both mobile and has a projectile that nearly plays neutral for him. It's not a fair comparison, because a combo game like snakes is all tech chased based and resets and proper setup, while wolf's is incredibly explosive at any time.
Wolf is crazy, the only thing that could potentially make him not the best spacie is the fact most characters still don't have a response to proper dd and nair shine from fox.