Smooth scrolling and smooth "back to top" by activate and forget.
Because there is no such link or menu item. If you need any customization feel free to ask at http://www.wpavenue.com/help/
You may download the PSD file from here.
Yes, just overwrite the arrow.png image or use the included PSD to tweak.
Yes, just edit the upperLimit value in js/jss-script.min.js.
Because these files are compressed. I have included reader friendly files i.e. js/jss-script.min.js and css/jss-style.js
Of course you can do this. I will add a blog post about how to do this without any plugin. But remember, you can't get automatic upgrade in this condition. BTW, Follow BlogSynthesis for any update.
Note: This plugin is based on "Cudazi scroll to top".