on your #4 why not just add the option from inside the search to click on the retainer you want to buy from and it warp you to the correct ward. i just feel that's 2 extra windows that's not needed in most cases.

example i search the wards for buffalo hides and find a retainer and price i want. it would save time to just select that retainer and hit go to ward. that would take me to the ward that retainer is located in.