I don't think Jim Beaver is, but he did visit the set W. Earl Brown said. He is dead on Deadwood. Titus has said on Twitter he is tied up in filming Bosch.
Here is a good summary of what happened to the continuing course of Deadwood at the time and what's coming up in the movie. https://en.wikipedia.org/wiki/Deadwood_(2019_film)
Not sure if the one of Doc has been shared here before. It was taken by his daughter a few months ago. The new one is Mr. Wu, posted by W. Earl on Twitter.
According to "E.B's" William Sanderson's fan page on FB, he is going back to LA for some more Deadwood filming... https://www.facebook.com/officialwilliamsandersonfanpage/
Found a treasure trove of trivia etc, how it really was in Deadwood, how the characters really were in real life etc. Good reading- https://www.legendsofamerica.com/we-deadwoodhbo/