According to Swedish newspaper Dagens Nyheter, and Magnus (the CEO), the Bumper cars will relocate to Furuvik, and Snake will occupy its spot during 2019, while the new Coaster is built. After that, it will relocate to another park within Parks and Resorts.
The area where the bumper cars and Biergarten are will have a complete overhaul, most buildings will be demolished and replaced, and the park will build a boardwalk along the water from Snake all the way to Bläckfisken.
Thanks for the pictures, I was wondering yesterday how construction was coming along as this is likely to be a very difficult build. It will definitely be interesting following this one. This will be a perfect case study to use for whenever someone says a park 'doesn't have room for a new coaster' for generations to come.