The best way to get in touch is by joining the channel #lumen on the Elixir Lang Slack. The ongoing work is discussed there and questions and answers can be had.
The news end up on the front page of this site but can also be accessed via RSS with this link.
The Lumen Core Team has weekly standups that are open to the public. If you want to join you can get the current information at the Elixir Slack which you can join here and you will find us in the #lumen channel.
We also provide the standups as video recordings on our YouTube channel. They will be in this playlist.