Wait.... Didn't someone in Slateport say something like, "The seaweed around these parts looks so lively, as if could jump up and attack"? Didn't ORAS have some dark subplot about Devon using Pokémon "life energy", which was you learned about in the Abandoned Ship? Are Dhelmise an indirect result of these experiments?
No.
>>32928741
That would be neat, but probably a coincidence since Gamefreak is so inept at world building.
They don't expect autists like us trying to connect little things and bits of dialog.
>>32928741
hint: life force is literally the fairies