So when I put a book on my wishlist on hold, does it still move up the line? Or is it held at whatever position the book was in when I put it on hold?

The Wish List Hold feature is different from the Bookshelf individual Hold feature in that you will move if the line moves on a book on Hold.

It just doesnt' offer it to you when you get to #1 until you take it off hold. But like Melanie says-it's different for the Bookshelf.  Posted books lose their place in line on individual hold.

Thank you