Regarding Sasha in Season 3, I don't think the opening shows her fighting the Wartwood peeps. Grime looks to be facing the same direction as the rest of the Wartwood characters, And Sasha's doing the "Cool character confidently looks over their shoulder" thing.
It's so hard to tell, because Sasha is onscreen for literally about 1 second. It’s possible that Grime and the Wartwoodians (is that a word?) are all facing an offscreen enemy, but it looks to me like Sasha and Grime are surrounded by angry frogs. Look at the two weapons at the bottom of the image that are partially offscreen; they certainly seem to be pointed at Sasha.
Maybe Sasha and the Wartwood peeps will only be enemies for a single episode, but my prediction based off of this screenshot is that they will at least start out season 3 fighting each other.
P.S. I gotta say though, you’re absolutely right; Sasha’s pose is pretty sick.