Just microwave or bake the flour then make cookie dough normally.
There is a much higher risk of getting salmonella from raw flour than from raw egg, since store bought eggs are pasteurized and washed (in USA/Canada).
Eggs in the shell in the US are not pasteurized unless specifically labeled, only about 3% of them, but they are washed. Any egg product out of the shell, like in a milk carton type container is pasteurized.
Everywhere actually. Salmonella in the poultry business was a huge deal and now the salmonella vaccines are some of the cheapest to produce. If your chickens aren't vaccinated you pretty much aren't selling them to anyone anywhere. I'm too tired to elaborate, but I used to work in the industry and salmonella in poultry is pretty much a thing of the past.
Salmonella vaccination isn’t standard practice in Ireland due to low prevalence of the infection. There’s effectively no salmonella on Irish eggs for sale. As far as I understand it anyway.