Train tickets delivery time

Hello! We arrive to Beijing on December 16th and leave the city on 17th. We need train tickets from Kunming to Dali on December 22nd. Problem is that our tour is very flexible and we are not sure about the addresses in between.
1. Will you be able to deliver Kunming-Dali tickets on Dec22nd to Beijing address before Dec 16th?
2. If not, are there night sleeping buses from Kunming to Dali?
3. Should I book bus tickets in Kunming and Shangri-La in advance or i can buy it the same day?
Thank you very much!