Play classic mode to see all the characters.
Other than that the only way you might be able to do it is by using the .gct fusioniser and using a code to force a character when you play.
[COLLAPSE="Code"]Costom Random V1 [spunit262]
06685824 0000000C
3C608068 7C630214
88630E80 00000000
046857F0 3AE000YY
06680E80 000000YY
ZZZZZZZZ ZZZZZZZZ
CSS Values
Needs "Giga and Company Engine V2" for Giga and Company.
Needs "Independent Pokemon Engine +no wreck My Music V2"
for Independent Pokemon.
Needs "CSS fixes for Giga and Company V2" for Both.
YY Number of characters
ZZZZZZZZ
00 Mario
01 Donkey Kong
02 Link
03 Samus
04 Zero Suit Samus
05 Yoshi
06 Kirby
07 Fox
08 Pikachu
09 Luigi
0A Captain Falcon
0B Ness
0C Bowser
0D Peach
0E Zelda
0F Sheik
10 Ice Climbers
11 Marth
12 Mr. Game & Watch
13 Falco
14 Ganondorf
15 Wario
16 Metaknight
17 Pit
18 Pikmin & Olimar
19 Lucas
1A Diddy Kong
1B Pokemon Trainer
1C Charizard
1D Squirtle
1E Venasaur
1F Dedede
20 Lucario
21 Ike
22 Robot
23 Jigglypuff
24 Toon Link
25 Wolf
26 Snake
27 Sonic
28 None
29 Random
50 Popo
62 Nana
5C Charizard (Trainer Independant)
5D Squirtle (Trainer Independant)
5E Venasaur (Trainer Independant)
4C Giga Bowser
55 WarioMan
4A ZakoRed (Red Alloy)
4E ZakoBlue (Blue Alloy)
40 ZakoYellow (Yellow Alloy)
46 ZakoGreen (Green Alloy)[/COLLAPSE]