My completely speculative take on this:
1. He publicly campaigned for Troy’s role (the biggest one in S2 after Hollanov)
2. He didn’t get that one but got offered something else.
3. That role wasn’t good enough or the shooting they scheduled for it doesn’t work with his other commitments.
4. This announcement comes before the S2 cast announcements which should be close and it helps him save face after the public campaigning.
5. It also helps frame fan expectations on known actors taking many roles
6. I think it will be mostly newcomers or fairly unknown actors, with maybe 1-2 bigger names in the mix.
7. I think with Troy and Harris they will try to copy the Hollanov “lightning in a bottle” formula with 2 young, unknown actors.
8. I still have Edvin Ryding for Luca on my secret bingo card
10. I think Wiebe, Wyatt, Kent and Crowell maybe known people.
11. I’m pretty sure we got already spoiled on Fabian.
12. Galina will be someone with Russian background.
13. Most Centaurs will be also newbies, as well as Ryan.