Well, it looks like a fairly balanced team. Here's what I have in mind for my mage, let's call him Mist (short for Mr. Mistoffelees, not that anyone on the street would get the reference, probably including Mist himself
).
Mist is a young (17) male human who grew up on the streets of Seattle. He graduated from child beggar to petty thief to cat burglar, and is now ready to make the jump to shadowrunner (which in his mind is like cat burglar, but with targets actually worth stealing from).
Physically Mist is on the small and lean side, a result of his childhood diet (or, often, lack of), with brown eyes and dark hair. His skin is a shade darker than normal for 'white', hinting at some Hispanic or possibly Native American blood. Or maybe it's just the result of spending most of his time outdoors for most of his life, but Mist himself likes to think he has some Native American ancestry.
At 14 Mist Awakened. Cat came to him in dreams, hinting at new ways to acquire toys and food. Cat did not explain any of them beyond dropping hints and sometimes gracing Mist with an unasked gift of invisibility or silence, but eventually Mist figured some of the tricks out, and found more tangible guidance in the form of a friendly Street Shaman, to the point that is now has a small but solid repertoire of spells. Mist, however, hasn't figured the tricks of summoning spirits yet, and does not know what to make of the astral.
Morally, Mist is of the 'anything that is not nailed down belongs to me, and anything I can pry out with a crowbar isn't nailed down' school of morality. He's vigorously opposed to physical violence, but that's because in his experience it always goes badly for him, not a moral statement.
Mist brings to the table decent* B&E skills, both mundane and magical, and a small list of street contacts. He excels* at Illusion spells, but is fairly useless in an actual fight beyond distracting the opponents with illusions. He is also fairly lucky. Mist comes from the streets, and has little in the way of expensive equipment.
As for what brings him to the attention of the Johnson, as a long-time runner of the shadows, Mist does have a fixer among his other shady contacts.
* 'decent' and 'excel' are meant to be understood in the context of a well-rounded, non-optimized build, where 8 dice is decent and 12 is excellent
