I think that it will be very helpful to have a button "Mark all" in Auctioning and then button "Post all" when posting. It will be faster to post all than the scrolling macro.
This is not possible. We don’t make people click on the post button for every auction because we think it’s fun.
Blizzard wont allow that as that will make it to automated and considered botting. The scroll wheel macro makes you do the easiest action possible to keep you from crossing into the automation that can get you banned.