I appreciate the information you have offered. However I already ruled / stated
Prerequisite: everyone is undead - this is met.Corrupted Wild Shape feat
Prerequisite
Undead type, wild shape class feature
if you can meet the Prerequisite, you can use it
Prerequisite: wild shape class feature - unless you have this class feature, you do not qualify.
No amount of alter self, polymorph, shapechange or the like can meet this, as far as I know.
There are very limited ways to meet this to the best of my knowledge.