Create Four Very Simple Cartoon Characters With Kid's Personality

Simplify Math Tutoring Center

I am opening a new math tutoring center where kids have fun with math. I want these characters to appeal to an audience that includes students between the ages of 5-18 (target audience).
Thank you,
Phyllis

I am opening a new math tutoring concept and want to have a few characters I can use as part of my website theme, logo, etc. These characters should be fun and relatable to kids ages 5-18. They should be fairly simple, because I will want to reuse them to create stuffed animals, video animation, and stickers, etc.
This is what I want in the characters:
a) A great example of what I'm talking about are the images from the headspace. They are fun, simple, colorful, appeal to all ages. https://www.google.com/search?q=hea…e&ie=UTF-8
( I obviously don't want to copy those designs, but I would like a similar style)
b) I don't want animals or people but like funny happy, goofy creatures with a lot of their own character.
c) Ideally, if the four can take on personalities of traditional kids - one may be class clown, funny, goofy, another more sporty but chubby (want to break stereotypes), third-thin, hip, trendy cool, fourth- smart, with a tooth hanging out, buttoned-up, or really WHATEVER you think could also work. These are just four ideas but have fun with it.
d) The color scheme and their design should look like they are part of the same family.
e) the color scheme should be a mix of warm and cool colors, but I don't want it to be too bright. Preferably on the more subtle side.

I know this was for one character development, but I'm looking for four simple ones that look like they belong in the same family so hopefully, that should not take more time than the one character with a lot of detail. I want to emphasize that these figures should be simple, not too complex.