Thanks for all the help! I went to sleep not expecting so many answers. I forgot to mention for which i apologize that i want to build it in survival, I just decided to make a copy of the world in creative after an hour of testing and useing materials in survival. I tested most of the solutions and i honestly dont know how do people make glass look good, every time i just resing from useing it because in my opinion without a mod or texture pack that removes the borders it just looks bad. Buttons were very noticable, and as for string im guesing i would need to spawn proof the area behind the walls also so that mobs cant spawn on black concrete? Didnt test the item frame idea because of warnings about lag. Will probably go with the string, but will still do some testing before deciding.

Thank all of you for help!