The night IC's will run almost daily from December 16th to January 2nd. The only exception is the night after Christmas Eve and New Years Eve.
Copenhagen-Hamburg 17.12. - 2.1. (departure is at 00:01 from Copenhagen, so it's the same nights the trains run in each direction)
Hamburg-Copenhagen 16.12. - 1.1.
Tickets for the international trains are one sale now. Tickets for domestic trains in Denmark through Christmas will be put on sale on October 19th.
The switch to IC1 coaches is planned to be on April 11th. But there is still a lot to be done before that can happen including the approval for the DSB Vectrons to run in Germany. Currently they are only allowed to run on ATC in Denmark. They are equipped with ETCS, LZB and PZB but Siemens has yet to deliver the software needed for the integration of those train control systems in the DSB Vectrons.
The coaches also needs to be approved for the Great Belt Tunnel.