This softcover children's book was published in 1991 by Golden Books. The book features the Muppet characters as young teenagers rather than as babies or adults, and is from a series of Muppet Kids books.
Here are two Muppet Kids hardcover children's books (above and below) published in 1992 by Grolier. The covers say "Jim Henson's Muppets" rather than Muppet Kids.
Here is a Preschool activity book with colour illustrations of the Muppet Kids that was published in 2003 by Bendon Publishing International. Four workbooks were included in the series along with eight different sets of flash cards. Bean Bunny is included as one of the characters in the workbook, and one picture shows that Fozzie has a younger twin brother named Freddie.
I'm not sure if any other books, toys or collectbles based on the Muppet Kids were made. These are the only items I've seen so far. However, the Muppet Wiki site has more information about Muppets Kids products which seems to have included a set of McDonalds PVC figures. Here is the link: http://muppet.wikia.com/wiki/Muppet_Kids
In the mid 1990s Jim Henson Productions started a new campain to promote the Muppet Workshop as a brand name. Among the most notable products that resulted were the Muppet Workshop figures that were sold at Mcdonalds restaurants in 1994. Below are all four figures, Dog, Monster, Bird and What-Not in their original baggies.