Stewie is a rabbit and also a Nerful. Nerfuls were a rather unknown line of toys from the mid-80s that were previously featured on BPA when Campy made an appearance. Stewie was a bit more well known since he just came with a board rather than a whole camp set. According to this bio he "is a smart-aleck, skateboarding rabbit who loves nibbling on radishes, peas, doughnuts, and other round foods." I've also included Frankie below on the board, a Nerful that came with a wagon. He looks a bit more like a skater to me.
Stewie and Officer Bob from the promo sheet. Even Parker Brothers knew that cops hassle skaters.