Additional Contact/Social info

Check out this plugin which adds social profile support for Guest Authors: https://github.com/Automattic/Co-Authors-Plus-Social-Pack

I don’t use Jetpack, so the Social Pack is not a solution for me.

You can do it yourself with the code provided here:

https://vip.wordpress.com/documentation/add-guest-bylines-to-your-content-with-co-authors-plus/

Except for when the plugin is update I lose all my changes….

nope. add that to function.php in your theme instead. the add_filter part is a hook. try it! it’ll stay as lobg as your theme does. you could also build your own plugin to hold it, to make it theme independent.