Can I book in advance and ask my Chinese friend to collect it for me in Beijing?

Hello! We have a friend who lives in Beijiing. We want to book a train tickets from Xian to Chengdu and from Chengdu to Kunming. 1. Can you deliver our tickets to her while we're still at home in Russia? 2. If we book the tickets now for December, when will they be delivered? 3. Do trains from Shanghai to Beijing operate on December 31st? And sorry for so much questions but there's one more: will the museums be opened in Beijing on January 1st?

Thank you very much in advance!