Grey - definitely don't add friends. However, you MAY pop up on other people's friend suggestions. I do all the time, but I don't know anyone! I said I lived somewhere else too. Different school etc.
I get 100 notifications of 'do you know ?' and 'do you know ?'
Occasionally it has got a friend suggestion correct only because I've been stalking old friends and it thinks you know them.
I think as long as you keep it all private, and don't add anyone, you should be fine. I have a group I'm going to join, which I am very excited about, and I couldn't do it if I was on there properly.
It's all good now, thank you 
I have a lovely DH, and 3 children. Occasionally I worry about past people etc, but mostly I just get on with life happily now.
Yes, poor empathy exists everywhere. Sadly. I've learnt lack of empathy is really bad in police officers, and midwives. TBH, anyone in the caring profession! As well as attracting the lovely empathetic ones, because of the caring nature, it also attracts the narcissistic ones because of the position of power.
My kids have it drummed into them all the time. Red flags! Watch out for this! Watch out for that! Look at actions, not just words etc etc.
My worst fear is that they meet an abuser. It ain't all cupcakes and rainbows most people are nice bullshit so I've prepared them to spot the ones that lack empathy in particular.