In the end, I fixed it myself. From the start, I suspected the code was working, but either I wasn’t calling it when necessary (because I had the initiations in the Begin Play event) or I wasn’t giving it enough time to run.
In the end, I fixed it by changing the order: first, creating the widget, then binding events, and finally, moving the AIcontroller cast from the Begin Play event to the (new) Possessed event.