Have you never said to anybody something like, "If so and so will do something, for sure another person will also do it?" ToTo me this was always a simple story about persistence in prayer and other faith actions with the judge who did not care what other people thought thrown in for emphasis. I thought I posted this yesterday. Forgot to click on Post reply.
Regarding Zacchaeus, in the English translations it is not clear that he is the one that was short. It might have been Jesus. As for it being a Sycamore tree, not all trees are easily climbed. Also details help the overall story to be memorable. If I said I saw an eagle in a tree, that would not be as memorable as saying I saw a Bald Eagle in an oak tree. Details that help form a picture in our minds help us remember.
One of the negative outcomes of Biblical criticism to me is attention to details that distract from the core message. Zacchaeus was a typical tax collector who collected more than was required for his personal gain. He did not feel right about his life which prompted him to make an extra effort to see Jesus. His experience of Jesus transformed him. His story has several messages for the community of the author of the Gospel of Luke. No one is outside the bounds of salvation or the community of followers of the Way. Transformation is available to anyone through an experience of Jesus. Getting to experience Jesus is worth an extra effort. With his reputation, it would have been dangerous for him to be in the middle of the crowd or try to push his way to the front. There is also the element of taking personal responsibility for solving one's problems.