Do you have both meshes to compare, tmp? I only have the DA2 meshes and that modding thread is like 200 pages long to dig through. >.>
I had the base body meshes but went and grabbed the inquisitor's default outfit too just in case. The results are... interesting:

the top row is from left to right, DA2 underwear mesh with Fenris head, DAI default outfit, DAI nude male elf.
Bottom row are overlays, to make the comparison easier. Bottom left demonstrates that DAI default outfit uses body downright identical with DA2 body. But, surprise, the nude DAI elf body has shoulders which are actually *wider* than what you got with DA2 elf (and what you also get with the default DAI outfit) The bottom mid picture shows difference between the 'nude' bodies in DA2/DAI. Bottom right shows the same difference between nude DAI male elf, and the same elf wearing default Skyhold outfit.
Conclusions?
#1, People talking how Fenris had wider shoulders than DAI elf haven't seen Fenris naked and go by impression created by his armour
#2, for whatever reason male elf in DAI has more than one body shape. That can happen with large projects like that and there's no way to know which is the 'intended, final' look, other than getting answer from relevant people privy to it.