RSS feeds would help aggregating updates from several people.
Before leaving Facebook, FOMO was a thing for me. But after I had left for a few month, I realized that life on Facebook had hardly anything to do with offline life.
The alternative for me is to ask people for their phone number, and keep contact via WhatsApp or Telegram with them, if I feel it was worth staying in touch. Definitely harder than just "be friends" on Facebook, but way more real.
WT.Social focuses more on the media part of social media.
I used to really dislike LinkedIn, but with a lot of social marketing/personal branding moving to Facebook, it might be time to give it a shot.
There's another one I can't recall the name of, but it focused on close and personal friends, rather than the 200 friends we tend to have on Facebook.
facebook alternative with a bias towards privacy
With that said, I don't really have social networking at all, but there's not much to be missed.
I use all of these. Plus Facebook.