[Kanon]

After reading your post, I realized that as I thought, I missed a lot of things.

Spoiler for episode 3:

So yeah, apparently, Ciel asks Sebastian not to tell anything about the case to Madam Red, so he definitely knows her and thinks she's alive. There is still one problem with the prequel theory: Grell and Sebastian met for the first time in S1 IIRC (feel free to correct me), yet they know each other perfectly here.

I'm pretty sure they are trying to make us think it's a prequel, but I don't think it's that simple.