Although there is a lot of local variation, after all America is the third most highly populated country in the world, I would broadly agree with this picture.
It's not quite as simple as that. Immigration can in some cases actually create more jobs in the economy, but in other cases doesn't have this effect, so its hard to pinpoint the optimal amount of immigration for economic growth.
This is true, but voters are not good at dealing with ambiguity, unlike (some) economists. If politicians muddy their message by focusing too much on the small disadvantages of immigration compared to its large advantages, it will make them look unsure of themselves.
Hopefully they can cut down on excessive packaging at the same time: packagingnews.co.uk/news/environment/amazon-customers-criticise-excessive-packaging-21-12-2015
I doubt this will offset the huge boost in emissions which will come with Amazon's 'Flex' service, which will see products delivered fast via horribly inefficient passenger cars, as opposed to relatively efficient vans and trucks.