I’ve been wanting to look closely at each of All’s Well’s mentions of nothing and establish the following for each one: (i) who says the word (ii) of whom do they say it (iii) with respect to what, then (iv) try to establish some sort of category to put it in. However, this is looking like a lot of work.
To take just the first one. “Thus he his special nothing ever prologues.” (i) Spoken by the king (ii) of Lafew. (iii) Unclear. The king seems to be saying that Lafew always talks up his enthusiasms of the moment in this fashion (though they are really trifles). (iv) Praise/ speech.
“Special nothing” perhaps we’d translate as “nothing special”; a footnote in my edition translates it as “particular trifle.” This is charged a little with meaning, I’ve got to say, because this “special nothing” turns out indeed to be something rather special –the plays heroine, Helena– which is what Lafew’s prologue is about.
So the answer to (iii) with respect to what, could be either “enthusiasms of the moment”, or “Helena”.
(Note this occurs in the second act and there are no mentions of nothing in the first act.)