“So the context is that every man is both a builder and a building...” No. Why? Because it says: “For we are God’s fellow workers; you are God’s field, God’s building.”
Notice: We work. You are what we work on (field / building). Contrast. For it to say what YOU say it says, it would read “For we are God’s fellow workers; and we are God’s building.”
Or, “We are God’s fellow workers, building ourselves”.
“...like a wise master builder I laid a foundation, and another is building on it. But each man must be careful how he builds on it.”
Each refers to the builders.
“Now if any man builds...each man’s work will become evident...”
Each refers to the builder. Obviously so.
It is not likely that you will ‘get through’ to someone who insists they must work to obtain righteousness. That is the core of catholiciism, that they must work to be worthy to eventually be born from above. Human pride is so deeply ingrained, it will reject the Promise of God if pride insists they earn what God offers by His Grace. It is as id they can insist that they had a hand in their conception and birthing ...
Even from your one-sided exegesis, it is the building that is burning and by burning is purified of straw and stubble.
If you want to suggest that “every man” refers solely to the clergy, the scene of cleansing still refers to the laity.