Is the CMC of a creature that is enchanted the cost of the enchantment and the creature combined?
The CMC of Filigree Familiar is always 3. The only time the CMC of a card changes is if it has {X} in its mana cost and it is on the stack (in which case it is the chosen value for X, other wise X counts as 0).


  202.3. The converted mana cost of an object is a number equal to the total amount of mana in its mana cost, regardless of color.