[Escell]

Check this article from an Australian paper about the GranCoupe launch in 2014...

It confirms the model will have a hatch boot like the Audi A5 Sportback:
http://news.drive.com.au/drive/motor-news/bmw-4series-grancoupe-confirmed-20131211-2z4u2.html

 

[bird]

I think liftback is just aussie terminology for hatch