It would be useful to add a button to the lock screen for starting a call with a predefined contact.
Then it is not necessary to unlock the phone every time you want to call e.g. your spouse.
Don’t you think that would pose a security issue. If you left your phone on the counter, someone can find out at least one of your contacts. Perhaps down the line pose as you?
I think it is a bigger security issue when I am on the station platform or in another crowd and have to type in my PIN and select my spouse from the list of recent calls (spy out). Further it may happen that some one snatches my unlocked phone from my ear.
I would feel more comfortable if I can call this predefined contact without unlocking the complete phone.
For the event of someone poses as me, I can arrange with my spouse to verify odd wishes on the phone by a keyword.
The steps may be slightly different on /e/OS, but you should be able to configure everything with the link above
The emergency contacts can be called from the lock screen by opening the unlock screen with the number pad and then pressing the “emergency call” button below of the number pad. Afterwards, you can select the emergency information where the emergency contacts are listed.
It might not 100% be what you are looking for, but it is IMHO close enough.