The way I use FB, it’s just a place to manage my in person contacts virtually. That’s the best, cleanest use for it I think. It’s not a popularity contest. You can always add someone and remove them later if they don’t seem like someone you want to interact with eventually in person.
Just think, if you add this person it means you might get an invite to their bday party or you could invite them to your bday party. Or if you have business meetings of some sort or if you’re interested in their business/art going-ons.. It gives you a way to stay in touch and stay somewhat involved in eachother’s lives. Comment on their experiences, offer suggestions, things like that. If you have no room for someone in ways like this, if you really feel they have no business in your life, then drop em or don’t add them in the first place.
Some are acquaintences, some are real friends, some are family. Just add whoever and remove whoever seems harmful. The rest can just stick around silently hoping for a day when your lives cross paths.