I've found some of the names to be reminiscent of particular characteristics of the monster- Regenerators, El Gigante, etc.
It is also often the Spanish version of a characteristic as well. For instance:
Colmillo: Spanish for fangs
Novistador: a combination of Spanish words 'No' and 'Vista', so together it's 'No Sight' or it can be translated into 'unseen creature'
Garrador: 'Garra' is Spanish for claw.
Armadura: means armor.