This is somewhat absurd

More than that, it's obviously incoherent. I assume your point is that the same should be said of zombies?

On reflection, I think that's right. I'm capable of imagining incoherent things.

I'll just note that the general consensus of the experts in conceptual analysis (namely, philosophers) disagrees with you here

I guess I'm somewhat skeptical that anyone can be an expert in which non-existent things are more or less possible. How could you tell if someone was ever correct -- let alone an expert? Wouldn't there be a relentless treadmill of acceptance of increasingly absurd claims, because nobody want to admit that their powers of conception are weak and they can't imagine something?