Proof of travel and accommodation for Visa application

We are Australian citizens and are travelling to Shenzhen in May to visit with friends who are also Australian citizens but working in China. We are flying in to Hong Kong International Airport and were then planning on getting the ferry to Shenzhen direct from the airport. We were going to book the ferry when we get to Hong Kong airport so we won’t have evidence of travel to and from China, but we will have return air tickets from Brisbane to Hong Kong. Also we will be staying with our friends at their private residence so we will not have proof of accommodation for our application. What do we need to provide to satisfy these requirements?