It is very plausible. Between Blue Umbrella and Alex Wesker, I'd say Chris is going to have a bunch of people working against him in this game.
You forgot Black Phillip's cameo!
While I agree that Resident Evil has always taken inspiration from other films/medias, I think the teaser for RE8 lacks things that feel familiar with things that feel more like Resident Evil. Visually, there are some interesting looking scenes, but it really doesn't depict anything that we've known from the series especially when things
appear to be paranormal. The trailer, shamefully, oozes the atmosphere of vampire and werewolf flicks and if Chris weren't included in the trailer (as well as a quick glimpse of the Blue Umbrella logo) you'd of never known this were a trailer for a Resident Evil game.
I actually am beginning to love the "witch" concept for an RE story. It goes along with the fairytale style that can be seen within CVX and Revelations 2. And with Alex Wesker's return, I think it is appropriate to play up on this a bit and what better setting than a small village for her to carry on with more of her experimental games. Something to also consider is that Alex literally transferred her mind over to a little girl's body, this is definitely something that falls under more supernatural themes, but Capcom managed to make it work for the game and many fans wanted to see the continuation of her story carried out to its fullest potential. Weather this game will do her story justice though, is another matter. There's a lot that will probably be skipped over with Natalia's storyline and that is something that is aggravating to think. While there's a chance to get things right, Capcom has also taken interesting story concepts in the past and turned them to crap.
Also, I think the theme of werewolves is really pushing this game out of the Resident Evil verse for me. Initially, when I heard there would be werewolves, I figured it would be wolves infected with whatever bioweapon that is going to be utilized in this game. But we literally see a male figure grow hair and teeth like in a classic werewolf movie... to see it in full context could help but from the trailer alone, it puts me off.