Hi Leo,
If I understood your project correctly you need CORE2-ROS instead of CORE2 
The only thing CORE2 is not available for purchase on the Husarion web site. Do you know when its become available?
All of our controllers will back to store in week or two ( I hope so
)
As far as RPLidar A1 configuration. In which config file should I make changes for TF? Also you mentioned about orientation, should I physically change A1 orientation on the robot platform as well, i.e. turn it 180 degree?
Please use just one of option that you mentioned. You just have to run static_transform_publisher like this:
rosrun tf static_transform_publisher 0 0 0.1 0 0 0 base_link laser_frame 100
with RpLidar A2 we have to use:
rosrun tf static_transform_publisher 0 0 0.1 3.14 0 0 base_link laser_frame 100
or physically turn your LIDAR by 180 deg and use instruction from our tutorials normally.
Best regards,
Hubert