You are all wrong Gamerad... I'll give the correct answer... Note all of these need the Subspace Emissary completed.
In order to unlock
Jigglypuff: you must go to the stage called *
The Swamp* in the Subspace Emissary. Right after Dark Didikong, you'll have seen a door somewhat nearby. Note that this is the first door you'll have seen. Go through it. Congratz, if you win you get Jigglypuff. (Alternatively, event 20, classic with any character, or 350 vs matches...)
Hardest to get to in Emissary, in the middle for finding. Toon Link:Go to
The Forest, where you first play as Yoshi and Link. After your VERY FIRST BATTLE, progress just a little further to the right. Go through this door, fight Toon Link, if you win... Congratz! (Alternatively, complete classic mode with Link or any other character after completing with Link. Or 400 Vs Matches.)
Easiest to find in Emissary Wolf: Beat the Subspace Emissary, and head to
The Ruins. Later on when you're at the area where you keep going down, and crystal spikes are coming out of the walls...
defeat all the enemies. Once you have done that, and you are at the bottom, there's a door that appears. Go through it. Congratz, if you win there's Wolf! (Alternatively, complete boss mode with fox after beating the Subspace Emissary, or play 450 vs matches...)
Hardest to find in Emissary I hope this helps!"Leaving your life behind"Smash Bros. Brawl Fc: 1590-4416-2207.