Have you ever tried crowd-sourcing this?
'Coz there's some forums and Facebook groups that cater primarily to the U.S. demographic that you're talking about.
Maybe by running some sort of contest or some promotion, you can get a sum from a large base of people to participate because you're looking for very targeted profiles.
Given the demographic that you're targeting, you're looking for something that is highly customized.
So I would suggest that you hold some contest to pull this off or you hire somebody who specializes in faux-U.S.A. or genuine U.S.A. accounts with older profiles.
Or they could change the profile for your campaign then change it back after some time.
I'm not sure if such providers exist here because your project seems to require a very high level of specificity.
But it doesn't hurt to ask and you might also want to consider virtual assistants to come up with U.S. accounts — that's fairly easy to do with proxies — and customize their accounts.
But if you need this very quickly, time is going to be a problem unless you farm out the projects to many individual VAs.