You could do them in any style or medium. They didn't have to be on model and they wanted you to express yourself. You could make a Scooby-Doo out of bottle caps or Atom Ant out of matches if you wanted. The main idea was that these might inspire some new products or style guide art that could be used at some point. Being that I always kind of look for something that might sell or something that I would buy if I saw it, I went to the young kiddie route and came up with Baby Yogi and Baby Scooby! I think they came out great and WB seemed to love Baby Yogi so who knows... I thought the baby line would be great for these characters since Disney has had such success with their Baby versions of Mickey and Winnie the Pooh.
For process junkies, these two were penciled and then scanned and just colored under the pencils to keep the clean rough look. It's a nice look for concept art.
Now L'il Scooby was actually the first thing I did and took the most time as I was thinking it would be cool for maybe a line of beginner reader books or something. I know he does seem like a Scrappy-Doo clone, but Scrappy is crappy and this is more of an ideal way to go. Even WBCP won't let you draw Scrappy for a job since they kind of disavow him. I never liked Scrappy's design either and thought Scooby "jumped the shark" when they started introducing Scooby's family in general. I had a young kid version of Shaggy to go with this as well. I wanted something cute and something that would appeal to women or mothers and that was what I aimed for.
This one was penciled, inked and colored with a painted background.