A team consisting of every playable fighter in the Smash Bros series runs this gauntlet:
vs Mercenary Tao
vs Piccolo Diamo
vs Piccolo Jr
vs Raditz
vs Nappa
vs Vegeta (Saiyan Arc)
vs Great Ape Vegeta (Saiyan Arc)
As in... the actual Smash Bros. versions of the characters, where they're just plastic toys that come to life and fight and they're all pretty much even in power (because otherwise someone playing as a Jigglypuff or a Pikachu or a no-name Animal Crossing villager would never be able to win a fight?) Tao stomps every last one of them with little to no effort.
Now if you're going by "the characters represented by animated plastic toys in Smash Bros., not the actual animated plastic toys" it's probably a bit different. I'm not 100% familiar with all of the characters, so I'm not sure how some match up (some of the new ones from the 3DS/WiiU version in particular), but I'll try to compare the ones I
do know of to that list.
A lot of them still get crushed effortlessly by Tao (all non-Mewtwo Pokémon, Olimar, the Star Fox crew, Samus without her power suit, Captain Falcon, Link, Zelda, Little Mac, Solid Snake, all or at least most of the Fire Emblem characters--some of them seem a little superhuman, but I don't know if I'd put them high enough to take on Tao--and of course all the random ordinary-human-level non-fighter guys like the Animal Crossing villager and Wii Fit trainer), but some could actually put up a good fight against Tao or even actually beat him. Mario and Luigi are capable of surviving a cannonball to the face or being caught in "standard human weapons grade" explosions, so unless Tao's grenade that sent him to the "replace stuff with robot parts" hospital was something beyond that level, pretty much any of the Mario characters should be able to beat him. Samus might be able to beat him too, if she can manage to hit him--Samus is not fast, while Tao is
very fast. So even if her Super Missiles and such might be able to do some serious damage to him, actually hitting him with one from long range would be hard... and getting close enough to him that he won't be able to dodge a missile easily would be very dangerous for her. Mega Man is in a pretty similar situation--some of his weapons might be able to hurt Tao, but he's not fast at all so Tao might just wipe him out before he has a chance to hit him with anything. Ganondorf is kind of a tricky one... too slow to even touch Tao, probably too weak to really hurt Tao, but the Triforce of Power makes him very difficult to actually kill so Tao would have to do something on a higher level than his "tongue-stab" to get rid of him... even a Dodonpa clear through the chest (like what he tried to do to Goku) might not finish him off, as he's been shown to survive a sword through the chest thanks to the Triforce. I figure Tao would eventually just get annoyed by Ganondorf's refusal to die in a single blow, then smash all of his bones and just leave him lying there unable to move for a while, counting that as a win as he walks off to do something else.
The vast majority of those who manage to beat Tao aren't going to be able to do anything against Daimao, though.
Kirby is decently powerful, but he doesn't really have much fighting capability without absorbing someone else's powers first, so things are a little trickier for him. His only hope of actually beating any of these guys without help is inhaling a ki blast and spitting it back at them (or swallowing it to gain ki-blasting powers of his own with which to fight back with), and he probably wouldn't be able to inhale anything more powerful than Tao's Dodonpa without Hypernova (and even
with Hypernova, inhaling a blast from somebody on either Piccolo's level is going to involve a struggle; the blast might just overwhelm him before he can muster up enough power to fully inhale it.) Assuming he can use Hypernova to inhale a blast from Daimao or Jr., he could probably beat them by firing their own blast back at them (swallowing it to gain the ability to fire ki blasts won't cut it here; in terms of raw power he just doesn't compare to the Piccolos, and when Kirby takes on a copied power it doesn't scale to the level of strength that the power came from--his Fire ability is just as strong coming from a random minion enemy as it is from a mini-boss level enemy, for example--so using their strength against them directly is the only chance), but he still loses to Raditz. If you give him the Star Rod he probably beats everyone up to Piccolo Jr. without too much trouble, though, considering that he managed to accidentally blow a hole in the moon in the process of destroying the Nightmare in Kirby's Adventure. Which implies that, with the Star Rod, he's capable of destructive power similar to beginning-of-Z characters (who can destroy the moon with an ordinary blast) rather than Dragonball era characters (who need a full-power, long distance, extremely focused blast like the Kamehameha to destroy the moon.) I still don't see Star Rod Kirby beating Raditz, though he might at least put up a little bit of a fight... the same Piccolo who could effortlessly destroy the moon with a single blast got the crap kicked out of him by Raditz and needed a lot of help from Goku
and a far more powerful attack to kill him, after all, so Kirby's not winning that fight on his own. Assuming that outside help (such as the fruit that enables Hypernova, or the Star Rod) is not allowed, Kirby can't get past Daimao.
King Dedede and Meta Knight can probably beat Tao (since they're usually depicted as being above the level of "base" Kirby and, unlike Kirby, can fight pretty effectively without relying on using their opponents' powers against them), but their inability to throw an opponent's attacks back at them turns into a huge disadvantage once they get to Daimao and I don't see either of them getting past him.
Mewtwo is among the strongest of the ones I am familiar with (Star Rod Kirby aside)... but his destructive capabilities top out around "blow up a building" level, maybe a small city at best. Like all legendary Pokémon, he just doesn't live up to the hype unless you're only comparing him to other Pokémon. Considering that his abilities are mostly telekinetic in nature with a few energy-blast style moves mixed in (contrary to popular belief, there is
no "mind rape" ability in Mewtwo's arsenal--almost all psychic-type Pokémon attacks are explicitly telekinetic, with only a rare few exceptions), he's basically Chiaotzu but with a body and mindset better suited for fighting. He's probably weaker than Daimao, but even if he beats Daimao he's not getting past Piccolo Jr. (and if somehow he miraculously manages to win against both Piccolos--he might pull it off if he's allowed to use one of the Mega forms, since game-stats-wise they're a pretty solid boost in power--Raditz still flattens him with both hands, both legs, and his tail tied behind his back. Yes, Raditz beats Mewtwo with a hair-slap attack or some kind of awkward flying headbutt... or a mouth blast, assuming he can use those.) Assuming Mewtwo can't use a Mega Stone to access either of the Mega forms, he doesn't make it past Piccolo Jr.
Ness is also way up there, probably above Mewtwo actually (though maybe not above the Mega Mewtwo forms); he might be able to beat Daimao considering that in his game he's capable of surviving an "Atomic Power Robot" self-destructing, and Daimao's blast was compared to a small nuke, but he'd most likely lose against Jr. too (and definitely wouldn't win against Raditz.)
I'm not 100% sure how powerful Sonic is, but I would have to guess that he's not really all that special if you don't count his Super Sonic form (speed aside... and even his speed isn't anything spectacular in Dragonball terms, considering that he's only supposed to be around or slightly above the speed of sound, which I'm pretty sure Tao's pillar-chucking flight is far beyond.) And he's not able to use the Super Sonic form "at will" like a Super Saiyan transformation or anything, so it's probably safe to not count that in normal circumstances--he doesn't randomly lug a full set of Chaos Emeralds around with him everywhere he goes, after all. He
maybe has a chance against Tao, but considering that his strongest point is speed and Tao seems to beyond him even in that area, that's a pretty big "maybe." I'm guessing he'd do a lot better as Super Sonic, but again, I'm not 100% sure how powerful he's supposed to be in that form (from what I've heard it seems like they're pretty inconsistent about Super Sonic's power from one game to the next, sometimes inflating things to absurd levels and other times... not so much) so it's hard to say just how far he'd go.
Unless Super Sonic is at least powerful enough to beat everyone up through Raditz (considering that it's a pretty obvious Super Saiyan knockoff, it's entirely possible they made the power boost on it
huge to match, so I can see that as a possibility), it's looking like Raditz is the "brick wall" that everyone crashes up against here, even if they manage to make it out of original Dragonball and cross over into the Z era.
Now, all of them fighting as a team against Tao, then Daimao, then Jr. and so on? They get past Daimao for sure considering that there's at least a few of them who have a chance against him to begin with, but I still don't think they can accomplish much against Raditz. If Sonic's allowed to use the Super Sonic form, he might be the only one who makes it past Raditz, and then it's no longer a "Smash Bros. team vs. these guys" thing so much as a "Super Sonic vs. these guys" thing.
Bulbasaur vs Pual (first appearance)
Ivysaur vs Yamcha (first appearance)
Venusaur vs Tenshinhan (first appearance)
MegaVenusaur vs Tao Pai Pai (first appearance)
Puar transforms into a jumbo sized weed-killer spray. That Bulbasaur is now just a "Saur"... and probably dead. Alternatively, Puar transforms into a flamethrower and the same thing happens.
Also: consider that Lance's Dragonite (one of the strongest non-legendary Pokémon, trained by one of the strongest trainers) can't even kill an ordinary human fighter with a Hyper Beam at point blank range. Considering that Yamcha upon his first appearance was not all that far off from beginning-of-Z Goku who is most definitely superhuman, Yamcha probably beats the entire 'saur family, with the possible exception of the Mega Venusaur... which Tenshinhan finishes off effortlessly.
