The client asked for a character which would be genderless and to an extent ageless. The video is supposed to appeal to everyone in the LGBT spectrum and therefor had to be non-specific but yet relateable. I wanted to go down a similar path to the 'Dumb Ways to Die' video by using characters which would normally appear in a children's animation but had a message intended for adults. Even with a simple design I wanted to go about it the right way by starting with character thumbnails. I used a technique I saw recently on youtube where the artist was working on character thumbnails for Thorin Oakenshield, albeit a very simplified version of it. After deciding on a set of silhouettes, you copy them a number of times and force yourself to try many different variations. You then work back into them with white to establish the details.
After choosing this character I recreated it in vector format (again in Photoshop, not Illustrator) and mocked up a couple of colour and shape variants. Creating the character this way means I was almost ready to import into After Effects and start rigging, only the multiple mouths needed creating.
I created the storyboard concurrently to the character design, although the character can change, it doesn't really matter too much if the model is slightly different in the boards when you animate (unless of course there are extra limbs or something like that).