Inversion with negative adverbs

I have never done this before. = the normal way 

Never have I done this before? = emphatic way = negative adverb + inversion (the question word order) 

What would you say this about: “Never have I done this before”?  

What would you say this about: “On no account would I do this”? 

Would this apply to you thinking back in the last month: “No sooner had I arrived home than I had to go out again”? 

Who would you say this to: “Little did they know that I knew what they were trying to hide from me”? 

If the negative adverbs go at the beginning of the sentence, do we use inversion or the affirmative word order directly after the negative adverbs? 

Is this use emphatic only?