I domt know the first and last, but the second is where instead of imagining the audience isnt there, you are talkimg directly to them. In some cases the actors can interact with the audience whole breaking the fourt wall.
Not sure about the 1st one, but it sounds like a cruel irony, or karma, where one does something bad, and later on the same bad thing gets done to you. Breaking the fourth wall is when a character in a comic, book, or tv show/movie talks to the reader, or states that he knows that there is an audience and he is just a character (comes from the old tv sets where there were only 3 walls, and the fourth wall was where the audience would watch in, and cameras would shoot: so when they "broke the fourth wall", they looked out at the audience and talked to them). Externalised conscience is essentially, as far as i know, when a character decides between what he wants to do and what he should do, and there are usually many soliliquies (excuse the spelling) while he makes the decision. Not sure if this is all 100% correct, but that's what my non-drama knowledge allows me, and hope it helps you out a little bit.
