As the author of the second question, I think 2 and 3 probably are very similar (perhaps duplicates), just out of unfortunate timing more than anything. The other question was posted slightly earlier, but mine is self-answered, so I'm happy to co-ordinate fixing that as appropriate.
I did try to specifically address the difference between 1 and 2 in the question:
I've read 'How much weight is given to authors' intentions in literary analysis?', but this question approaches the issue from the perspective on an academic, whereas I specifically want to address questions where more casual readers want to check if their theories are 'correct' and how a reader can decide the method of analysis for themselves.
I wanted to focus in on the misconception of 'correctness' rather than just discuss what academics focus on. Later in my answer, I've tried to reflect that by giving some practical steps for non-academics to follow. If you have any suggestions to further differentiate that, that'd be immensely helpful.
It was also my hope that my question could serve as a starting point for a canonical question to link confused questions to (see What to do about questions that confuse author's intentions with a text's meaning? for context) since I can see your point about addressing the issue in every question as being repetitious.
Let me know what you think about it though—I didn't post my question with any slight against yours, I was just unsure that it really fit as well under that one as opposed to one specifically targeted at a person analysing a text themselves. If you can see a way of merging these together, I'm happy to do that.