it is possible to know which playercontroller(instance?) triggered an event in an actor? For example that a player that presses F jumps 1 meter and another (who joined later) 2 meters?
No, except if you just make a new input for the jumping event, and send some sort of ID through about who called the event. It would be useful a very few times, but it wouldn’t be easy to do, and the programming languages doesn’t work like that. It would create a lot of useless traffic if it would be sent by default.