The rabbit is holding the horn because he blows the horn every time a person is called to the stands on trial. Yes I believe that the rabbit Alice followed down the hole is the same rabbit that is in wonderland. Everybody wants Alice to leave because she is always messing things up. She is growing to big in the court room and is tearing everything up in the room. Alice is forgetting everything because she is starting to wake up and reallize what's going on. The mad hatter is not on trial. He is just a whitness for the stands.