I’d just use a line trace to get reference to the actor you are attempting to send the interface message too, so you don’t need to deal with an array. This also would negate the need to check for the class type, because you simply need to see if it implements the interface. Just use the camera’s/ players’ forward vector * float to get an end location for the trace.
Also, why not have the text message be returned in the initial interact interface message? If the NPC doesn’t have a “secondary interaction,” it should be easy to ignore the blank returned text.