Zhang has been a TOP 10 HW boxer for some time now. And Eric "Butterbean" Esch never came close to that level. This seems like a frivolous question to me (Who wins?), considering that Butterbean is a 4-round boxer.
This indirect question from Miniq hints at whether Zhang is a formidable adversary for Fury. If Zhang can defeat Butterbean, the answer is a resounding "no," as Butterbean is considered to be on par with Fury's opponents. If Zhang slaps Butterbean, no chance Fury goes near him. Zhang stops Fury in 10.
Well, I once beat Mike Tyson on the hardest difficulty in Fight Night Champion using Butterbean. That has nothing to do with the question, I'm just still amazed I did it after only a couple of tries. Anyways, Zhang by early KO. Then we can all ask "Is Butterbean okay?" and mean it.