I've only repeated what you've said, I've been careful not to put words in your mouth. It's important to understand how your language affects the rationale of others.
It's a very in-depth question. For starters there are many combustion products, to what extent they play in psycho-activity has been a matter of debate, but as far as I'm aware, has never been a topic of research.
There is also the ratio of vapor to vapor condensate, as well as droplet size that should also be added into the equation, with wispy vapor having a higher ratio, and smoke having a lower ratio, generally speaking, though there are a great number of factors affecting each of these aspects.
BTW, on a fact-checking mission I found out your previous statement was incorrect, CBN is an oxidative degradation product of THC, not a decarboxylative product. That being said one must also consider the extent to which the starting material has already been decomposed, as that will affect the cannabinoid ratios, which will affect the effect.
That's just for starters, there's a whole long list of factors that must be considered, this is one of the more complex drug interactions due to the sheer number of variables that must be considered, mostly due to the enormous variances in administration techniques, as well as variances in starting materials, which have widely varying compositions, and lets not forget storage, which affects degradation, so on and so forth.
I would like to research this kind of thing to help the public understand the roles each of these interactions plays, because when this substance becomes acceptable for recreational use, many people will want general guidelines on avoiding intoxication, where as the knowledge of how best to harness the medical value can be better determined for our current legal status.
Either way there's much to consider, and much to know, it will take time to document it all and determine what's what.