Yes. They have been shown to be self-aware and aware of their surroundings, which satisfies the classical definition of consciousness. Unless you reject that definition, I'm not sure why you'd claim this.

Cats haven't expressed self-recognition in the MSR test. However humans younger than 18 months also don't pass that test. So to say it is a measure of conciousness is quite a stretch.

I'm not an expert either, but my understanding is that "consciousness" is still so poorly understood that it's more the realm of philosophy than science.

In particular, we all know that we're conscious, but can't really explain what that means.