With few exceptions, Tippi will always be at your side. She'll constantly keep you alert of the latest happenings, in addition to providing tips throughout the game. You can also point your Wii remote at the screen to find hidden things, and gain information about anything. Her passive use is to remind you of what you are supposed to be doing, and that will be triggered by pointing at your current hero, but these hints will not give you direct orders, they only state what your main goal is but not how to complete it.
Thoreau is the first of the selectable Pixls you'll find throughout the game. His hand-shape is no coincidence, for he's an expert at grabbing and throwing things. Press "1" to grab/throw something. Throwing is constantly used to throw a block of some sort to activate a switch. Thoreau's passive ability is to grab nearby dropped items and bring them to the player, but any dropped item that can be found is able to simply be grabbed if the player touches them, so grabbing items is useless. He can also grab Boomer.
This guy is an explosive. Although his specialty lies in blowing open damaged walls, he's also great for blowing up enemies. In addition, you can detonate at anytime by pressing "1" after setting him down. Any way, if you wait long enough, he will blow up by himself. His passive use is to be picked up and thrown by Thoreau, but placing him and switching pixls is highly inconvenient.
Turn paper-thin with this Pixl's awesome power. Not only can you fit into small gaps, such as the between the bars of a jail-cell, but if you stand perfectly still, enemies can't even harm you! You'll also appear to be invisible while standing still.
Built brick tough - this Pixl allows you to perform a 'ground-pound,' which is great for hammering objects into the ground, suck as pillars or switches. It can also make for an effective attack against slower enemies.
Carrie is platform that you can ride around at high speeds. Not only that, but it can float over water and spikes without being harmed.
Fleep can flip objects around, as if they were a sheet of paper! Use his mad skills to find secrets hidden throughout the land. He can also make enemies dizzy with his flipping powers, making him a valuable aid. You find him waiting in a bathroom stall in space, having waited 100 years for toilet paper.
This Pixl is a total tool…but in a good way! His hammer-shape is excellent for destroying large bricks that block the road. He's also makes for an excellent weapon.
Dottie can shrink you down to size, allowing you to enter miniature structures, such as the tiny shops hidden throughout the land. In fact, you're so small, enemies can't even find you!
This optional Pixl is just as much about offense as he is defense. Use him to place a force field around you temporarily that not only will deflect just about any attack, but it'll also cause harm to anyone who tries to jump on you.
This unique Pixl appears to be worthless at first, but can actually be quite useful. Her most obvious feature being the sound effects that are altered (depending on which main character is out) once she's equipped. Her ability also will cure poison effects.
This difficult-to-obtain Pixl endows the gift of speed. You can get him after you defeat the Pit of 100 trials in Flipside. With him, you can roam the landscape at high speeds, which can reduce your travel time significantly.
Although Tippi is no longer a part of your world, you can regain the use of her powers by purchasing a near-perfect duplicate of her. Give Francis a visit in Chapter 3-4 after beating the game to discover that he has created a near-perfect clone of Tippi, named Tiptron. You can purchase it from him for a cool 999 coins. While pricey, Tiptron will allow you to use all the same power's Tippi had!
A gallery of all the pixls: