It could be nothing more than coincidence.
There can be a whole bunch of reasons why one plant will do better than another.
Take for example the 3 cuttings I have from a Hibiscus. All 3 were taken at the same time, put in the same size pot with the same compost and kept in the same conditions. All were taken from the same plant and were roughly the same thickness and length.
In the spring, all started to show equal signs of growth. Today one has shot way ahead of the other 2 despite all 3 continuing to be treated exactly the same.
The fact is that two identical plants just a metre or two apart can show different growth rates and flowering. Sometimes there is just no rhym or reason for horticultural differences.
I have to agree with RD, in that it is unlikely that the extra CO2 is enough to make any real difference, even if it is 15 or so times a day. And I rather think that the smoke would not be an effective insect repelent.
Differences in the plants performance can be affected by the soil drainage, nutrients and other surrounding plants. There could be an unseen underground blockage causing the soil to drain slow, leaving the plant roots in too much water. Or there could be a nearby tree depriving a plant of sufficient water. Clover growing near one plant would have the effect of replacing nitrogen in the soil. Great for some leafy plants, not so good for some flowering plants.
There are so many factors to consider. A tree or shrub growing 10 or 20 metres away may have an effect, but an extra 5 metres might be all the difference it takes to change the soil conditions.