Will wearing special outfits during smile time affect a child?
It appears that the children of two dwellers are some combination of the statistics of their parents. But do the outfits they are wearing at the time factored into their stats?
No, as there is not a real correlation between parents and children at all. Only the C value seems to correlate a bit but this can be just luck.
If your dwellers wear a suit which improves C it will lower the time till smile time.