Using Stylish:
.username, .ulink, .user_link{display:none;}
^^ Didn't know could be that easy, although the script doesn't work everywhere and also removes ratings in game pages but for now this will do more than enough for me, maybe I could modify further later if possible.
So thanks a lot chess240. Much appreciated. I'd rep your entry if I could :)
There is a Chrome/Chromium extension that adds a checkbox at the top of the page that hides opponent information, rating, and spectator list. It may not work well for kid mode because the checkbox can be unchecked.
chrome.google.com/webstore/detail/lichess-hide/mgnmffmefjnmmpcbjmhepgclaaegcamjFunny, everyone asks for a way to hide ratings, now a way to show ratings. You also might want to add the class ".user" to that list for the crosstable at the bottom.
I agree with Cynosure. However I believe this should be called "Safe Mode" rather than "kids mode" since there also exist people other than kids who also do not like certain things such as people in certain religions, people with certain views or just people that are easily offended.
Animal names + numbers are nice. We can still make this alternative name unique for every player..such as I will be called Cat2719.