Most smart phones have the ability to have a group of contacts which are accessible on the lock screen, for example if you have to eat hospital, the staff should be able to access your ICE contacts without needing to unlock your phone.
On my previous phones I used the ICE group, and any contacts there were available on the home screen, however this doesn’t appear to be the case on the Fairphone. Is this possible through some other method? Or is a feature which requires a newer version of Android to work out the box?
I guess there are apps which provide the functionality you are talking about, but the easiest way would be to go to Settings > Security > Owner Information and put the ICE numbers there.
There are many apps, however a lot of them haven’t been updated for a few years. One that has been recently updated, will show the emergency numbers but won’t allow you to call the number without unlocking the phone which is useless. Newer phones allow the ICE contacts to be called from the lock screen.