"And Mary and Aaron spoke against Moses, because of his wife the Ethiopian" (Douai version)
Ethiopians are semitic people - the Amharic. For a long time theirs was a joint kingdom with Sheba, which is in Arabia. As far back as records go, they worshipped God following the pre-Temple pattern of the Hebrews. They have become intermixed to a great degree with the black Africans over time, but they are certainly not originally of Bantu or Nilo-Hamitic ethnicity.
However, this begs the question of what is exactly meant by the term, due to its wideranging use and the variety of peoples living there.
The Catholic Encyclopedia notes on Ethiopia:
"It is not easy to determine to what part of the world the name Ethiopia properly applies in the course of history. The territory it covered, and even the use of the word to denote a territory, have varied in ages and at the hands of different writers. In the early pages of the Bible Ethiopia is used to designate the lands inhabited by the sons of Cush, and is therefore applied to all the scattered regions inhabited by that family. Such a use of the word is purely ethnographical. Elsewhere, however, in the Bible it is applied to a definite region of the globe without consideration of race, and is thus used geographically. ...
Concerning Nubian Ethiopia: "The races which peopled these regions differed considerably. In the valley of the Syene as far as the junction of the Arbara the population consisted for the most part of husbandmen of Egyptian extraction. In the plains of the Upper Nile, side by side with some negro tribes, were a people allied to the Himyarites, and who had migrated thither from southern Arabia, while others again showed that they owed their origin to the Egyptians and Berbers."
Concerning Abyssinian Ethiopia: "The modern Tigré. formerly the kingdom of Axum, would seem to have been the kernel of this State. It was founded by refugees who came to the African continent when the Arsacidæ were extending their sway in the Arabian peninsula, and the power of the Ptolemies was declining in Egypt. These refugees belonged to the Sabean tribes engaged in the gold and spice trade between Arabia and the Roman Empire; their dealings with civilized races had developed them, and, thanks to their more advanced stage of mental culture, they acquired a preponderating influence over the people among whom they had come to dwell. Still, the descendants of these immigrants form a minority of the Ethiopian people, which mainly composed of Cushite tribes, together with an aboriginal race called by the Ethiopians themselves Shangala."
While concerning Cush it notes:
"The African Cush is best known; but there were Cushites in Asia. The "land of Cush" of Gen., ii, 13 (Heb. text), watered by the Gehon, one of the four rivers of Paradise, was doubtless in Asia. Regma, Saba, and Dadan (Gen., x, 7) were in Arabia. The Madianite wife of Moses, Sephora, is called a Cushite (Ex., ii, 16, 21; Num., xii, 1-Heb. text)."
In this latter vein, you are invited to look into the location of the land called the Hindu Kush even to this day.
Why one should, based on this, rush to the conclusion that Moses married a black woman, is beyond me. This belongs in my mind in the realm of myths of St. Augustine being black, and the Egyptians themselves.
According to you, Miriam and Aaron stirred up an almost-rebellion against Moses based on his marrying a women who was closely related to the Hebrews.
Does not compute.
It is much more logical that she was able to tap into latent prejudice among the Hebrews against people who were noticeably different.
BTW, I didn't invent the idea. Many scholars, including many Catholic scholars, agree.