i know that a wizard with lore of death can kill even "standard" models with the spells from the lore, but if he uses spirit leech on a model with only a wound and make (for example) 6 wounds can he roll for each of the wounds he made for the lore attribute? It would be awesome against armies with low leadership like skaven or goblins, expecially if you have another slann
I do not think it works that way. The spell targets a single model. If it has only one wound, that is all you can roll for.
The wording in the BRB for the death attribute specifically mentions purple sun only rolling as many dice as the model has wounds on its characteristic if it is removed. That being the case, the same approach should be applied for other spells.
I would actually argue the opposite. I think because it specifically points out Purple Sun that the other spells wouldn't follow that same trend. However, I do also believe that it should only grant a die per wound that the model can actually take before being slain, I just think the Purple Sun argument doesn't give any credence to it.
I dont think it is a mistake that they have both of those entries in the errata. The Ogre book is uniquely full of close combat attacks distributed as shooting, impact hits and stomps, i assumed it was saying that if a wizard gets stomped by a greedy fist bearer and takes a wound, they lose a level. As far as lore of death, I cant think of any place in warhammer where you get a benefit from over-killing something, except in challenges where there is a special rule dedicated to it.