For the mannequins they are "posed" already, but you can "dress" them. You can buy clothes at the bazaar or win them (whatever your preference is) and when you click on the mannequin it will show you how to "dress" it.
As for the number of ingredients...well, it's the joy of crafting. It's a patience thing. Gather stuff as you go around the worlds. Get the transmute recipes and that makes it easier for the number of diamonds you need. It's like that for any crafting recipe really. Transmute recipes are essential.