Analyzing country data. Does duplicating observations by population for regression make sense?
I see what you're doing, and understand the thinking behind it, but don't think it makes sense with this problem. By assigning 300 variables the same values, you're effectively saying that each of these million people have the average economic output (i.e., if you're using GDPpercapita) for all the people in your dataset. That's a pretty misleading understanding of the distribution of that variable, and will lead to poor analysis. Same goes for other aggregate factors. 

If you're looking to do a regression where those are incorporated into your analyses, using the unscaled population data as one of your features will include that information as one of the coefficients you return. So you can get back the result on happiness of having a million more/less people. No need to duplicate the data.