Hi,
You are getting there! So if I didn’t misunderstand you, the torch light up mechanism is working right? However I am a bit confused about the setup. I hope you only created one blueprint with the torch light up system not one for each torch 
What I can see now, that in the last picture you attached you are checking the value of the boolean not setting it. Use a set node there, and set your boolean to true (because the torch is now turned on). You will want to check all your booleans at the gate, to see if all of them is true.
For the gate opening mechanism I would use the Level Blueprint, but others might disagree on this with me. Give me some time, I’ll try and find you some proper explanation about how you could implement the gate opening logic, if I can’t find I will try and help you myself, but I am no expert, so take everything I say with consideration.
[EDIT]
After some research, I agree with the solution that was offered by the guys above me (with much more experience), you should use Event Dispatchers. Have a look at the link that SaxonRah sent, it should get you started on how to use them.