I know you can import other stuff like object from another .blend file. I am wondering if you can do the same of the line styles and how?
Yes we can import/append /link the freestyle save the file with freestyle When import / append with the with the other folder of texture lamp mesh object you get the folder of Freestylelinestyle
Open the folder and append/link
In the Render -> activate the freestyle option
After import/append under Render Layer in properties panel -> Under Freestyle Line style select the line from the drop down.