Instead, they have to be completely remade for the remastered versions. The issue stems from original trilogy mods not being able to be ported to Legendary Edition automatically.
On the blog for ThaneMOD updates, creator Giftfish announced an hiatus from the Mass Effect modding community, explaining that the mods were deleted over concerns that others would copy them in Legendary Edition without permission. The creator of a popular Mass Effect 3 mod which added much more content for Thane has taken all of her work offline.