Falchion I think the Shimenawa could use a bit of adjusting in a way I can't even describe properly because spriting is not my area of expertise at all, but hopefully this analogy will help:
The closest thing I could find on a sprited Gen V pokemon that looks like rope is Hitmonlee's legs(left is the B/W sprite, right is the HG/SS sprite). The lighter parts of the outline of the legs in those sprites look exactly like what you have for the outline on the Shimenawa right now, but there's sections where a black outline is used for parts of the leg too, specifically the areas opposite where highlights are used. I like your Shimenawa a lot but I think using a darker outline color alongside what you have for it would help it stand out much better, especially in the bow part of the backsprite. The 'sleeves' in the front sprite look a little asymmetrical to me and I feel the Shide and rope on the front sprite could be cleaned up a little bit too but they look fine to me in the backsprite and as with everything else, that's up to your discretion.
This is also super nitpicky but I think changing the highlights on the shiny's mask to White, if you want to use a white-like color for them, looks nicer than a light grey, even though literally no other voter will probably care. I would also recommend against using the same color as your base colors for the highlights you have on the alternate gender sprites but, again, that might not be that influential/worth the trouble to change.
Sorry for all the criticisms but I really like your sprites, you've done a really nice job in my opinion!