Other things you might think about.
Distinctive Features: Mage.
Maybe even Martial Arts type Style Disadvantage so that people would know you are a Pyromancer and then they could guess what spells you can do. What you can't do, weaknesses etc.
Analyze Style would come in handy.
KS: Magic, Famous Magicians, Magical Styles, famous magical Artifacts etc. could all be complimentary rolls. Stealth, concealment etc. could all be bought specifically for magic to hide your traces.
One thing you might consider for extremely sneaky or subtle mages is Invisible Power Effects, Invisibilty, Darkness v magical scrying etc.
And lastly as my mind explodes with the possibilities you can use Martial Arts for Magicians who regularly go into mystical combat (Doctor Strange movie!!!!)