You won’t have yet. The creative stuff will be mapped out over the next 12 months - GAW are famous for being very careful over their franchises and will want to have as much control over the writing as they can.
Assuming GAW and Amazon are still happy It will then progress onto production so we’re probably 2 or 3 years for a show/ movie to be ready.
When Henry Cavill first emerged as being involved in this there was some talk about him being Inquisitor Eisenhorn. I haven’t seen anything since but you are right there are a lot of possibilities. I’m not that familiar with 40K characters or storylines I’ve always been more interested in the fantasy variants of Warhammer and am only just starting to follow the futuristic stuff.
I told you a while back that I’d only just started getting into the lore (my word, it’s a massive, massive world) because one of my best mates talked me into starting to play Warhammer 40K: Tacticus on my phone (hence me asking a few weeks back if there were any White Dwarf readers who were willing to give me the code that came with one issue to unlock one of the characters - yes, I’m an addict, don’t judge me! ).
By the way, IGN speculated that Cavill would play Primarch Roboute Guilliman (which would make sense since he’s a key character from what I’ve managed to gather so far). However, since there’s a big time jump in the lore, perhaps he could play multiple characters?
Prime dropped the first 3 episodes the Friday the week before Christmas then it’s one a week, bastards. Easy to watch, interesting story line that will keep you engaged and need to pay attention and great fight scenes. The humour is an added necessary bonus to lighten the gratuitous killings.
The books are great too if you’re looking for something to get into.