I have a vapor genie, and I would think that less gas is inhaled than with a conventional pipe because, with the genie, the heat goes through the ceramic filter before it hits the weed. Interesting question, though. I do tend to use the lighter more with the genie than with other pipes. Doing a google-search, other than badly-made or defective throw-away lighters, I couldn't find any information about health problems from lighters at all.

Insense is not very healthy to breathe, so I don't use it.

Your question(s) probably would be appropriate for the "medical" forum.