Hotstuff or Hotdog (the Fire Wolf) self-explanatory
Dextrus or Dexter (the Grass Raccoon) refers to the raccoon's characteristic trait of being very dexterous with its front paws. the origin of the word raccoon derives from its ability to use its paws as hands.
Amplehop (the Electric Rabbit) self-explanatory with a play on amp/ ample
Willfreed or Willyfreed or Wilfreed (the Water Whale) refers to the popular movie Free Willy
i would also suggest Dick Moby if that passes the nsfw test. it may not as it would seem to be a suitable screen name for a well-endowed male adult movie star. i thought i should suggest it anyway because at least in the english speaking world Moby Dick is undoubtedly the most famous whale of all.