Sure but in that case its still Person Y that should be liable (Person Z merely reprinted their remarks).
Unless there's some weird edge case where Person Z republishes without Person Ys permission or in conspiracy with Person Y but that's why we have courts in the first place.
Depends on whether the defense of innocent dissemination applies. Usually if you're not the first person to publish it, or if it was reasonable for you not to know the thing was defamatory, you're ok.