3 Answers

Who can see the Friends section of my timeline?

By default, everyone can see who your friends are in the Friends section of your timeline. To change this setting:
Go to your timeline
Click on the Friends section under your cover photo
Click at the top of the page and select Edit Privacy from the dropdown menu
Use the audience selector to choose who you share your friend list with on your timeline
Note: People may see mutual friends when they visit your timeline. Your friends also control who can see their friendships on their own timelines. If people can see your friendship on another timeline, they'll also be able to see it in News Feed, search and other places on Facebook. 

https://www.facebook.com/help/115450405225661?sr=14&sid=0oboA9oCRM4S7xy7i

You can message them  on FB and the public will not see your personal message. You can talk to them live---like an I M  if they're on FB when you are. Nobody will see your live chat with them.