Since we are aiming this at a younger audience, and what to make it feel very fun and entertaining, I am looking at a lot of Cartoon Network-esque styles for inspiration. their bold lines and colours stand out a lot (which is also the sort of thing that helps merchandising wise, and since we are thinking about this with the potential to be a series, I think that making opportunities like that for ourselves is a good idea).
Fairlyodd Parents is one of the shows that I think of first when I think of Cartoon Network; it's style is very iconic, and allows for a lot of expression and movement. The faces use the same formulas for each character and doesn't offer so much variety, until you get to the older (and especially male characters), apart from when the Faries are being silly. The colours are very bright and interesting, and the lines are very thick and bold making it very appealing to a younger audience. With the body sizes and shapes for many of the characters, there isn't an overabundance of detail making them easier to watch.
Powerpuff Girls is another on of the most popular and influential styles from Cartoon Network. Their designs are extremely simplistic which makes them easy to read, especially as they have fairly small bodies that may be hard to decipher otherwise. Bright colours again help to make them stand out. Their body shapes also makes it very easy to map out the line of action and plan how the characters move.
The Grimm Adventures of Billy and Mandy use very good, different silhouettes which make them unique and gives them a lot more personality; you can tell that Grimm will be a much more serious character from all of the sharper edges he has, and his taller, stretched out figure. Billy on the other hand is made from rounder more friendly shapes, showing that he is a harmless kid and the bubble one of the group. Again they simpler colours not only for their younger audience but to show the younger age of some of the characters as well.
Thinner, coloured lines doesn't subtract from the bright colours of the characters which emphasises their personalities and setting. The bodies are extremely simplified, putting more emphasis on the faces and accessories than the actual clothes themselves. There is decent variety in their face shapes which can't always be found with female characters of the same age in animation.
Great diversity and very good silhouettes. Upbeat, lively, full of colour - reflects the possibilities of imagination rather than the real world so much. There is a lot of variety in faces and shapes in this, which helps because the characters aren't limited by human shapes, sizes and proportions. They aren't even all real animals, so arguably the designs are limitless (when you don't think about network restrictions etc). That doesn't mean a design has to go crazy though - Bloo is one of the most simple characters on the network, but he was still one of the most popular with his naughty personality.
In Samurai Jack, there is much emphasis on shapes; the designs also feel softer with less lines which probably helps the show get away with more violence. Faces tend to be tackled in a different way to some of the other CN designs, which is in part because of the attention paid to other cultures. Detail within characters is much more subtle it helps to show the character's personality, but it isn't distracting - the main focus in Samurai Jack is the silhouettes, done especially well with the more villainous characters.
Sym-Bionic titan has a slightly more realistic style - compared to the above few designs, anyway. You can tell just from that that it is aimed at an older audience, with a lot more detail and thought for style and how people think about their 'image'. the colours are slightly more varied but still very bright, to make it friendly enough for any younger viewers watch it. It still keeps the thick lines, keeping it very bold and exciting.
Gravity Falls, from Disney XD uses a lot of the techniques from above but actually has a few more changing outfits for the characters, depending on what happens in the episode. These tend to be similar in shape and style to their usual clothes, and still reflect their character and personality very well, keeping them recognisable. The lines aren't thick enough to take away with the design - it seems that thicker lines work better for more extreme, compact designs; Gravity Falls has a lot of slightly more realistic proportions, even if the shapes themselves are very simplified,and they use thinner lines than many of the examples above.
These designs give me a lot to think about; I know that silhouettes and bright colours will be an important part of my design, but the amount of exaggeration depends on what exactly we decide our final story to be, and just how young an audience we are aimed at. These designs can also apply to the food, especially if we end up having any food as characters.