Though, the Aldudagga is from Breton sources, isn't it? It'd make sense for the Bretons to see Sheor = Greedy, but what about the Skaal? Especially if the Skaal's Greedy Man becomes Thartaag, it makes more sense to apply that label to Alduin. Unending hunger = greed, thus Alduin = Greedy. It makes no sense to apply the title of "World-Devourer" to Shor/Lorkhan.
"And of the Giants we speak little, even less to strangers, for their history is hidden in long loud power-shouts. At home, it is a pain in the ass to tell their stories and then clean all the things knocked down in the telling... and in a foreign hearth it is [just plain rude]. So we speak of them (for we must-- who does not honor their parents?) under the rim of the sky or, here, written on sheafs of pelt, for such is the mettle of their threat. This is [a song (or dirge, manuscript unclear)], then, of the threat of Giants and, like most, it involves painted cows." - Aldudaggas, Fight Six: "911th Cow"
Snow whales and 911th Cow (as shown above) are very specifically Nordic tales, told by Nords, as is apparent no matter which Fight you open up. Honestly, I'm genuinely curious: where on earth does it say the Seven Fights of the Aldudagga was written by the Bretons??? Where could you have gotten that? Because Fight One's Greedy Man is most definitely Lorkhan who hides in Red Mountain, and the Skaal and Nordic Aldudaggas are the only ones to reference Alduin and the Greedy Man together (or mention the "Greedy Man" at all) that I've ever heard.
Also, from Varieties of Faith. Sheor is specifically, the "Bad Man", not the "Greedy Man." The Bretons have never once called him the "Greedy Man." I mean, the Bretons don't even acknowledge Alduin as a deity in Varieties, which is the only time on record "Sheor" is mentioned.