I've had my own ecommerce craft shop, not on Etsy. If you don't have a lot of different types of items but have multiple colors and styles, have ALL of them up. A lack of a big inventory doesn't need to look like you have bare shelves.
There isn't one. You basically need to scape everyone for the data unless they give you an API. This gets pretty hard. I know a startup in Singapore that could probably help.