For each of those services, their APIs will have different data available. Just a quick search shows me that total follower count isn’t available for Facebook, for example. So in some cases, it might be easy, but in some, you might have to scrape the page to get the data out.
In either case, you probably don’t want to do it constantly, so I’d probably just pull the numbers once or twice a day, and then fake the live part by just having them increase randomly (like they do on Reddit now) to give a sense of activity.
This would be a project suitable for someone with a fair amount of web development experience and knowledge of Python/Flask or something equivalent.
Edit: Missed the Squarespace tag at first. You’d need to hire someone.