CM = Complete Mage, right?
To answer your question in order
No, they are not spells. They are considered Supernatural Abilities.
Since they are not spells, they cannot be influenced by metamagic feats. There are some feats that can affect supernatural abilties.
If a saving throw is allowed, the DC is equal to 10 + the level of the spell allowing the ability's use + the ability modifier you would apply to that spell's save DC.
All this information can be found on page 36 and 37 of Complete Mage.