You are a mage, you definitely need a Talismonger.
You should get a fixer for mundane gear and jobs.
That's the minimum setup. imho
Knowledge skils...
again you are a mage it hurts not to get
magic theory
and I think somebody made a good point that parazoological threats is more effective then magic threats as a knowledge skill, but in the end both are probably worth it.
You are going for an assassin, so security tactics and security design is probably not wrong (how do they respond when I assinated someone and how to plan the way out as well as where are weak points to enter&exit)
If you are going to orient around umaro's occult investigator you can too check which knowledge skills and contacts he has and get inspiration from there,