Thinkpad T61, latest 18.04 update. I tried having the only user with Automatic Login set to yes. With power up boot, the lightdm screen comes up as opposed to going directly to the desktop. The lightDM shows two users, my only user and another one named Other.
LightDM Login has "other" user
Did you try installing the package ‘lightdm-settings’ and configuring autologin and manual login from there?