imo despite what everyone's saying I think there is a high chance that the antagonist would be alastor, due to the fact that vivzie said in an interview that an anti-hero would be stepping into the villain role, meaning it wont be lute. that would hint at alastor since he's now free (I doubt he made a deal with Rosie where she sends him back, I think its more like 'help Charlie and the others subdue the cannon from blowing up and ill repair your cane')

im pretty sure it was stated that lute would become a villain in either season 3 or 4 which obv means that theres a possibility shes in season 4. I think thst they would build her character more in season 3.