I'm using wallpaper engine for the ghost wallpaper
Yes! You actually need wallpaper engine on your pc and on your phone, and use the pc version to send the wallpapers you want to your phone's wallpaper engine.
You cannot search and subscribe to wallpapers via your phone
The icons are from a pack called Retro Mode - Light (it also come with customizable widgets for the text and stuff) The launcher is Nova.