Moose/Goose Adoptive parent argument

My friend and I have had this argument. he does not seem to believe that Moose/Goose LAID the eggs of the Moslings despite the similarities.

does anyone know for certain?

his argument is that the names we see in-game are named by survivors.
my counter is that since Maxwell basically made and named EVERYTHING in the "constant", at least he, if not everyone would know most actual names after he became stranded on the very same island he created.