[@Rune_Alchemist] Ha, it's good to see you working hard but don't overwork yourself. 

If you burn out before the start of the RP you are no good for me ¬¬ [s]joking joking[/s]

To answer your question, a Pythones mage would be able to control any spirit at any given time effectively AS LONG as it falls under their jurisdiction. 

Example. A Pythones: Water Spirit mage is able to use spirits of water scattered about anywhere, independent of whether they have used them before or not.

HOWEVER, if a Pythones mage is possessed by a powerful spirit, they could summon that spirit to fight AND have another kind of Pythones magic in full effect. 

If this does not answer your question, just tell me and I'll go even more into detail with it.