Japanese just use kodomo as in child
良い子だね iikodane would suffice if talking to the child or telling someone about them.
You may say 'imouto.'
"tsuki komodo"
Kashikoi ko
hiko
the world child? you can say SEKAINO KODOMO(TACHI).
'black haired child' is "KuroKami No Kodomo"
You may say 'nakuko.'
tora no hotondo
chisai kitsune
'Little fire' translates toå°ã•ãªç‚Ž (chiisana honoo) in Japanese.
小熊(koguma)