Of course we don't know all the facts but it's fair to assume that exactly the same evidence was not presented to the GJ and to UK. Also, it's extremely likely that the accusor and the accused both testified at the UK hearing.
No, there is no way Tubman testified at the original hearing. There is also no way that hearing had more evidence than the GJ. The difference is UK needed only a preponderance of guilt. I'm sure Tubman spoke at the appeal, but as with most appeals, you will only win if you prove an error or oversight in the original hearing. Thus, Tubman couldn't win an appeal because he can't prove a negative. I will once again voice my concern over UK, or any school, holding a "civil" hearing while a criminal investigation is ongoing. It is unfair to the accused and defies what our country usually accepts as due process. If the alleged crime is serious enough, the accused could always be suspended from campus until an outcome is reached. Then a student conduct hearing could happen without an automatic bias against the accused.