what is naming day and how would it be celebrated
Well, I’m not sure about when it happens, but, as the name would suggest, Naming Day is traditionally celebrated with giving Matoran new names, and is otherwise sort of a magical cyborg Christmas with gift giving and such.
I think the reason naming day exists is so lego could have a canonical reason to change the names of their characters because of the Maoi language controversy.
Right. Naming Days happen twice a year, at which Matoran who have performed great services get recognized with a new name.