Here's an idea. Use a service that generates phone numbers that redirect to your actual phone number. Maybe Twilio. Just as some do with email addresses.

Create a new number for each use. For each family member and friend. For each site registration. For each whatever.

Have an app that searches periodically online for all of those numbers. If any of them show up linked to Facebook, or whatever else concerns you, nuke them. And maybe ping whoever/whatever got that number with an admonition, saying that they're no longer a trusted contact.

That would be extreme, I know. And you'd need to cut some slack for close family, your employer, etc.

But would it be doable?