1. The Creature look is changing only when you equip different class of head (Archer/Warrior). Changing other body parts affects the Creature's stats: resistance, HP, etc.
2. Creature parts being move in some.. well... in some vessel in another dimension where can be available an any time. I'm no sure if those being transported from Nabreus to your necromancer, but it does not really matter, since you will get MUCH more powerful body parts at that time.
Same applies to formulas.
