I made a short story for why I think it's named Bonfire.
One day on a cold winter, the Ferals were freezing. They gathered in the center, conserving their warmth. One Feralheart spoke up, "W-We s-should build a b-bonfire.." He said, his teeth chattering. The others nodded and collected wood. One Feral got some flint, and struck the wood. A huge fire erupted up. The Ferals cheered, no longer cold. The snow melted and the fire was so warm the island would never freeze. The Ferals put the fire out and began playing. But before they broke up, one Feral spoke up, "We shall call this island, Bonfire Island, in honor of the Bonfire that saved us all!" They all agreed on the name, and from then on, the island was called Bonfire Island.
Ands that's how Bonfire was made XD