Basically, they hire actors to push Will out of the company to make him look crazy and film it.But, the actors also give sage life lessons to everyone else as well.It's revealed that the Collateral Beauty line that Naomi Harris quotes is actually from Helen Maureen when she magically visited her.The very last scene is them standing on a bridge looking down upon Will (they're lit like angels mind you) Will looks up at them and they disappear.
------------------------------------------America from 9:00 on: https://youtu.be/GUwLCQU10KQ