Hi,

how can i set up a group formation for my party on a PS4?
And something similar: how can i change the order of characters? I see that the order sometimes changes after seperating and then re-joining, but i have no clue about the rules.

Unfortunately, there is no way to set the group formation in the controller UI.

In the party selection screen (left trigger), when you select a character not at the top of the portrait order for the current group, there is an option to 'Move Up' by pressing the square button (X on Xbox controllers).

Cool, good to know!