

Doesn’t matter, as you elaborated more deeply on why das Mädchen has neuter gender.
BTW: The use of (das) Fräulein (miss), again a diminutive; ‘little woman’, in German, to refer to an unmarried woman has come out of fashion since ~50 years and now may be perceived as insulting as well.
Mädchen is no longer perceived as a diminutive of Maid or Magd, as both terms are more used in a historic context, and thus, it stands on its own.
Onto your first con: The swordfish isn’t an ungulate nor even a mammal.