Okay, several points here....
The Cealla is the Sithi version of a Mage (i.e. from the core rules), a single profession. They have no connections with Harpers.
You can have Harpers that use the same Tradition as the Cealla or who have their other methods.
As for the colored components -- that is how Sithi mages view magic, as a rainbow of color (like Skittles), and the stuff in their pouch works to aid them in drawing on that magic. So long as a Cealla has his pouch, he should be considered to have enough components to cast spells (i.e. no need to track what is in the pouch, so long as the Cealla keeps looking for things to add).. He doesn't use fixed mana, per se, but his components are normally consumed in casting. Occasionally, he might find an item of exceptional color and hue (i.e. it grants a special bonus to casting)
And please, don't confuse "Traditions" with the focus and source rules from CoM, they are two completely different, unconnected things.