If you've looked over my three posts on the Undead Enchanted Undead, Cursed Undead, and Restless Undead, you may have noticed I have a slightly different take on undead than some game systems. I do not believe in "mindless" undead. In the Shatterworld setting, all animated matter is driven by the platonic concept of Nous, or 'mind". That is, if you want something that isn't alive to move, you have to summon a spirit to take possession of the object. You can then order that spirit around, if it is cooperative. Some spirits are less cooperative than others.
Thus, while a golem might not be normally considered undead, the premise behind animating it isn't any different from animating a skeleton. If the skeleton is considered undead, so must be the golem.
However, a skeleton, or corpse of any sort, animated by a necromancer/sorcerer type is quite different from a corpse animated by its rightful owner. In this case, we have a revenant... a putrefying corpse that refuses to stay in the grave. The difference between an enchanted corpse, and one that is cursed, would only be discernible by the actions of the corpse. Even that might be a guess, because a corpse could be possessed by a spirit that is trying to fool you into thinking it is actually the person who's body it has taken control of.
A ghost is undoubtedly the spirit of the deceased, but in this case they don't have their body to trout around in. It is possible that by destroying a revenant, you simply create a ghost or wight. This would all be circumstantial, and depend on how long you want to drag out a storyline.
Hopefully, you will find this structure of undead, even if it does not seem intuitively correct, will provide lots of fun in creating stories and encounters. Happy haunting!