How do you say goodnight little duck in french?

It's cute (ᵔᴥᵔ) .. As a native French, I would say:

'' Bonne nuit petit canard ''

Or:

'' Bonne nuit mon petit canard '' ( more affectionate than the first one).

Bonne nuit mon petit canard.

Bonne nuit ma petite cane.

Is that "little duck" as a small bird, or as a word designating a beloved human?

Bonne nuit mon petit canard

You can say mon canneton

French language has specific nouns for a baby of an animal

Ex chat - chaton (cat)

Chien - chiot (dog)

Renard - renardeau (fox)

Lapin - lapereau (rabbit)

Girafe - girafon

Éléphant - éléphanteau

Lion - lionceau

And so on

Bonne nuit mon petit canard (Good night, my little duck).

Bonne nuit mon caneton (Good night, my duckling).

Good night, in the sense of: done for the night/ going to bed.

Buenos noches pavo pequeno

Bonne nuit petit canard.