Entity-Being-Bearer-Character

Since the gameState only contains entities, how can all the other classes of the "Entity's hierarchy" (Being-Bearer-Character) be used ?
Entity need a Species object to be instanciated. Species contains fields like baseHP and the like. I thought pure Entities (ie. not Being, Bearer, Character) weren't, by design, supposed to have such statistics. Am I correct ?
I'm beginning to think that the Entity's hierarchy should be collapsed. Removing Being, Bearer and Character and putting everything in the Entity class. Of course, I don't mean that Entity should get all the fields and methods from Being-Bearer-Character (the file would become messy), but instead, in the spirit of Species, I think we should create objects containing all the fields and methods linked to a given "feature" of Entities. Example: Instead of the Bearer class, we create an "Inventory" class containing the fields and methods from Bearer, and we add an field in Entity storing an object of type "Inventory". What do you think of this ?