It means 'what is the nickname of your last child?'
a nickname
"Enfant" translates as "child".
"Fernier" is not a word. Do you mean "dernier"? The word "dernier" means "last". For example "le mois dernier" = "last month"
Il est enfant unique
"un enfant placé" is a child in foster care
'votre' is the possessive translated by 'your' in English.
"un enfant placé" is a child in foster care
I am a child (it should be - un enfant)
"Deuxième prénom de mon premier enfant" translates to "Second name of my first child" in English.
Un enfant parfait (masc.), une enfant parfaite (fem.) means "a perfect child" in French.
Un enfant terrible is a troublesome child. Being an 'enfant terrible' is being someone special by his breakneck or foolish behaviour: Michael Jackson was the 'enfant terrible' of the soul music.
"votre jolie ..." means "your pretty ..." (fem. noun).