Light Top Knotch is something I'm considering using for my own Haku cosplay. You'll need the
Pruning Pinchers to remove some of the hair ornaments. I don't think the bow can be removed, but, personally, I'm fine with this. If you don't like this item, perhaps consider using light colored buns like I have.
For his mask, I'm thinking of looking up Noh masks and masks inspired by them. Maybe you'll consider the same? I'm sure there is an item guide that has something a section for such masks.
I have the item you are questing for, but I'm not selling it. If you have the rest of ur cosplay ready and still need it, I'll loan it to you for the duration of time you plan on wearing your cosplay. You can also consider increasing your bid if the current offer is yours. It's almost 50% of abp. Not many would go for that if the item wasn't inflated. If not, I wish you luck! The price has been going on the decline.
Ponderosa teal is also a color I think matches Haku quite well, though I haven explored the tag to see if there are any items there. If there isn't, have you looked under the teal tag?
I'm sorry this isn't much help, haha
sweatdrop