In #1, the meaning in the two sentences is the same. This is not the case in #2 and #3. The as in #1 = because. I'm not sure how to help you clear up the confusion.
Thank you and you already did! So If I were a bird, I could fly to you means As I am not a bird, I can't fly to you but If I were you, I would hire him does not mean As I am not you, I will not hire him, right?
One problem with this sort of analysis is the use of the word 'means' or the symbols ? and =. "If I were you" does not 'mean/equal' (or 'not-mean/not-equal') anything else.
All we know for certain if a speaker utters these words that is that the speaker is not 'you'. The speaker me