I wonder if it might be easier to create this concept as a Human-PhysAdept. (Newt grown up Anyone ?)
Magic-C
Cash-D
Human-E
You get an extra Edge, 5 Power Points, 2 Skill Points, full Essence, and essentially all at the cost of 2 Charisma.
5 PP gets you
Reflexes-1 v/s Wired-1 (Same Effect)
STR+2 v/s Muscle-2 (Same Effect)
Agility Boost-2 v/s Muscle-2 & Elf. (Minor Loss here)
And you still have 1 more full PP to spend on things like ......... Combat Reflexes, Pain Resistance, Improved Skill, Improved Accuracy, More Agi Boost, Senses, etc etc.
Take a Mentor Spirit & pick up some dice & extra PP abilities........ Shark - Killing Hands & Unarmed Combat, win win there.
Rat, Eagle, Wolf, Wise Warrior, Dragon Slayer...... any of those also add nicely to this street urchin concept.
And then you don't have to explain where all the cyber cash came from.
Heck, if you really wanted to, you could take STR-Boost-1 (or more) and have her only be able to tote the MMG while she is boosting, which I think will make for a VERY interesting concept IMHO & give you points back to use elsewhere.