Learn English – “Advise” vs. “advise that”

In general, when you use a countable noun in the singular, you must put some indication of quantity in front of it. When you use it in the plural, you may give a quantity or not. By "countable noun", I mean a noun that refers to something that can be counted, like dogs or bricks, as opposed to things like liquids that perhaps can be measured but not counted. By "indication of quantity" I mean a number, like "one" or "six"; an article, namely "a" or "the"; or some other word that indicates a quantity in some general sense, like "many" or "some".

In this case, "not a big deal" uses an article to express the quantity, namely, one. "No big deal" uses the word "no" to express the quantity, namely, zero.

So in your "stupid question" example (I'm referring to the example you give, not your question!), yes, you need an article or some other "quantity" word. Normally you would say, "That was too stupid a question" or "That was a stupid question".

Note that you don't necessarily need a quantity when you use the plural. For example in the singular you cannot say, "There was dog in the room", you must say, "There was a dog in the room" or "There was one dog in the room". But in the plural you can say, "There were dogs in the room." You CAN give a quantity, like "There were two dogs in the room" or "There were many dogs in the room", but you don't have to. (I have no idea why this is so. It's just the rule.)

OED says that this use of the word consulting does in fact mean giving advice and stems from a now-obsolete sense of the French consulter, to give (professional) counsel. They suggest that the word should be parsed as a noun used attributively, rather like "loudspeaker" in "loudspeaker cabinet", "a cabinet for a loudspeaker". Thus a "consulting engineer" is an engineer to whom one goes for a consulting.

consulting, adj.
2: Applied to a physician, engineer, etc., who makes a business of giving professional advice, either to the public or to those practically engaged in the profession. [ < French médecin consultant, ‘celui qui donne des consultations’ (Littré); from obsolete sense of consulter to give (professional) counsel: compare “consultation” n. 2c. But as now used consulting would be understood as an attributive use of the verbal noun.]

consulting, n.
The action of the verb consult; consultation. Also attributive, as in consulting room.

However, this is the only way in which the word consulting is synonymous with anything to do with advice. The normal uses are as quoted in the question: one consults someone who advises, and the words are practically antonyms.