Help with light switch puzzle

Hi everyone, so, I created i puzzle that needs to switch light colors to open a door, and i have two questions about it.
First one: The puzzle dont work in the beggining, it start working if I switch each color a couple of times, then it start working, i dont know why and how.
Second one: After play the sucess sound, i need to set a variable to true, and that variable I want to play the proximAnimation2, wich is the animation of a door, but I have doubts about how cast this class and it nodes.
I’m begginer in Unreal, so please be patinent.
Here is the video of the puzzle I used for this:

Edit: I found out that the light order number NEEDS to be one more number than the light int, why? If i want to change this, how can I do?