I think the useless characters are as follows
Nack the weasel, Bark the polar bear, Bean the dynamite, Jet the hawk, Wave the swallow, Vector the crocodile, Espio the chameleon, Big the cat, Daikun the koala, Colonel the koala, Kylok the koala, Muzy the koala, Setter the koala, Tabby the koala, Zavok the zeti, Zazz the zeti, Zor the zeti, Zomom the zeti, Master Zik the zeti, Zeena the zeti, cream the rabbit, Vanilla the rabbit and that is it. This is my opinion and if you disagree feel free to say so in the comments.