crap.
What I`m using is a third party plugin for controller (https://www.fab.com/listings/b41984a2-53dc-4187-a564-cfd23af5df08), and just listem to them on first controller, and redirect the call to the other pawn, so all my local controlled pawns for split screen are actually sending input to first player controller.
So on the controller setup, I just have basic number that I add on the character instead of relying on the player controller object, then on the widget, lets say “Press any key for 2º Player”, at this moment I only record the device index, then use this to identify which character each device is controlling.
Everything will come as Player controller at index 0, so I just don’t use the player controller, instead where I need to know which player it is, I save the device index.