I am not familiar with the author, Eisel Mazard, that you are quoting. There are many confusing articles written by people who just get the meanings of Pali words from dictionaries (written by those who have no real understanding of Buddha Dhamma.)
His following statement is wrong: “The Pali word is gandhabba, and this is a sort of “heavenly musician” that could be described as the masculine counterpart to a nymph: a sensuous and somewhat insouciant sort of sprite, often depicted as part of the entourage of the more powerful gods.”
– In addition to the “human gandhabba,” there is also a category of “gandhabba Devas.” Another sutta mentions a “gandhabba Deva,” who is a musician. That has given rise to this notion of gandhabba as a “heavenly musician.” I hope you can see the confusion! This is just one example of confusion created by bad translations.
Many suttas refer to human gandhabba. That author is just not aware of them. See, “75 results for gandhabba”
When a human existence (bhava) is grasped, a manomaya kaya (with a hadaya vatthu and five pasada rupa) is created by kammic energy.
– Then, that manomaya kaya waits for a suitable womb.
– During that “waiting period,” that manomaya kaya can “absorb” scents from flowers, etc., as food and become a bit “denser.” Thus the name gandhabba (“gandha” + “abba” where “gandha” means “aroma/odor” and “abba” means “to take in”) See #2 of “Hidden World of the Gandhabba: Netherworld (Paralōka)“