Chinese speaker here. Actually, 耗羨 Hào Xiàn isn't even supposed to be any sort of mythological creature (at least from what I've known), it means extra tax government took from you for extra costs, such as wild mouses ate up some of the tax rice. Although the Nine sons of Dragon do have different variations, and Chaofeng did later derived into Chiwen or Ao, it's bizarre how Haoxian got mixed up into this. I've even found a Hungarian website talking about Haoxian being an alternative title for Chaofeng 😆
Right? That is absolutely crazy, it is like someone called Mothman ''Federal Taxation'' lmao. Also, so that's where the ''mouse'' thing Bates mentioned in his book came from.
It is good to finally have the confirmation about the real meaning of the word, becasue it makes this search even funnier. Now i do believe even more in the theory of mishearing from Bates part. Id love to talk with him one day, but it do not seems possible.
I hope our investigation makes spreading of accidental misinformation in Chinese culture a bit less prominent now, at least. Thanks for your message!