[PF] Frostfallen template question

[Azoth]

OK, so I have a player of an aspiring Necromancer character. He brought to my attention the Frostfallen Creature template. A question arose when going over it.

Are they Skeletons, Zombies, or their own brand of undead?

Obligatory link to the template in question:
http://www.d20pfsrd.com/bestiary/monster-listings/templates/frostfallen-creature-cr-1

In the Hit Dice section, it has a note about skeletons using their Charisma to determine bonus hit points. In the example creature, it calls the Frostfallen Mammoth a Zombie. I have no clue on how to rule it.

The reason it is of some importance is that if they are skeletons or zombies, then they are eligible for other templates. While template stacking can be expensive I know this player would gladly pay the cost for Frostfallen Bloody Skeletons. After all, the Life sense alone makes them walking encounter detectors.

[Kallimakus]

It is my understanding from reading the template that they are their own breed of undead (as the likes of Burning Skeleton are found under the skeleton template, while that is not). I would imagine the reference to skeleton on the template is a holdover, rather than calling it a skeleton. In practice, I'd call the two templates mutually exclusive, as both need to be applied to a non-undead creature.

Another question is whether te charisma of a hypothetical bloody frostfallen creature is 12 or 18. My guess would be at 12, personally.