A very good list.
That being said there is one mistake.... Laughing Dog.
A duck Hunt stage would be much better then this. Honestly what is good about Laughing Dog, what moves could he possibly have. Who could he possibly go up against. If anything there should be a Duck Hunt game simulated into Smash Bros. and you get to kill the twerp.
I do like the rest though.
Mach Rider: I don't know much, but from what's i've heard this is actually the game that inspired F-zero. I believe Falcon's was even based off Mach Rider. So it would be interesting having a Mach Rider vs Falcon match huh?
Geno: I'm starting to doubt this guy's chances. There's has not been much talk about him lately. And I can see Sega and Capcom taking the other two third party spots.
Krystal: I like it. The Rod opens up a cool new set of moves too. It be nice to get another female character in. (Not that i'm up for hot girl foxes, I reckon because Smash Bros has too many male characters it could end up being classed as sexist.)
Deoxys, Lucario: Don't know my Pokemon. But i'll support any as long as they get rid of Pichu.
Skull Kid: He's got a good look. But I really don't see him getting in. What do you mean this guywas evil. The mask made him evil. Not to mention you hardly ever fought him, so how could he be cooler then Gannondorf. He could be very unique, but right now Midna has a better chance than Skull Kid.
Ridley: This guy is actually a Flyer so it'll be very interesting to see how he becomes a smasher. Maybe the Smash Bros. Melee intro could give a hint on how he would fight. But he is the best pick for a Samus enemy.
Dark Samus: I'm not a big fan of the Metroid series, in fact I have never finished a MEtroid game, but I do like Samus in Smash Bros. And I have played Metroid Prime and it is an annoyance to finish. (I'm still having problems.) But if this boss is as good as you say she is, then bring it on.
Samurai Goroh: I actually see this guy making it this time. It's just his size that worries me. Then again Wario has made it, so I guess that's not a problem.
Bubble, Ray 01, Ballon Fighter, Claus, Lip: No idea on any of these characters. but if G&W, IC, Marth, Roy, and such can satisfy me I'm sure these characters could too.
Wolf: Don't know Starfox series too well either. (Hey I had a Sega Mega Drive 2 instead of a Super Nintendo.) But I know he is Fox's enemy. And Fox needs an enemy more then an ally, I just hope he isn't a clone.
King Deedee: Not a Kirby game fan. But Metaknight looks cool I'm sure this guy is even better. And He's a Penguin. Which could be interesting.
Bowser Jr./Shadow Mario...... I just don't like Bowser Jr. but I guess I got to support him the fact he's been in a lot of Mario games lately. He has a good chance. It's just a pity cause I preferred the Koopa Kids moreso. At least they had a sense of humour too.
Ike: Has the best chance out of any FE character. He will replace Roy I feel. However he probably wont replace Marth. Marth is Mr. Fire Emblem. Not to mention he is one of the few lords to be in two Fire Emblem games. I also reckon FE could have 4 spots this time. It certainly has grown popular and with Goddess of Dawn coming around I reckon they should promote characters again. Miciah and Sothe would be great additions too.
Toad: I reckon he's still got the best spot and should lose it. Then again he did finally become a character in Mario Party, so it's only am attoer of time till he join the Smash Bros. roster. But hey with Pichu most likely gone, this guy could be my new punching bag.
Megaman: Ooh how I used to love the old Megaman, don't know what happened to him today. But when he was on the NES his games were awesome. I have a bad feeling though Capcom might use another character. They have really been making a lot of RE games for the Wii, so my best bet is it's one of the RE characters most likely. Leon vs Snake could be a good match. I would prefer Megaman though.
Sonic: I support Sonic 100%. And I hope he makes it. I just finished Sonic and the Secret Rings today... and I reckon it's the best Sonic game i've played in a decade. Finally Sega have got back on the right track. Still needs improvement though. But anyway, Sonic would be a very unique character, and the Sonic vs Mario argument needs to be settled once and for all, it shouldn't be done at the olympics it should be done in Smash Bros. Also Sega always seems to sell better with Sonic on a NIntendo console then the other two, and Sega has helped a lot with the VC on the Wii. Downunder anyway.