About stamina go to Scripter -> Persistent -> Variables, in line 56 you have:
["stamina"] = $stamina <= 850 and true or false,
850 is time in minutes, you can change this.
There is not "regular necklace", it just using amulets/rings which you set in settings (you can disable it ofc). I've never tried to use authenticator and have no idea how it working, so feel free to try