well i just got this type of idea from another indie game.
when u get a namechange there, in your profile is a line which says "Before known As ...." where "...." meant to be the old name.
this way u can know who the person with the new unknown name is.

i dont think its that hard to add such a part in the user profile. may it just gets added to those "mini statistics"
im bad at making an pic for that.
may someone is so nice and just takes the mini statistics and adds such a line too it.