Welcome to Shadowrun! A few comments on the concept:
Summoner-Face is a viable build, and an old favorite of mine. However, this build is likely the most karma-hungry I've seen.
It needs Karma for:
i) Several Initiations just to get the Metamagic you need. (with Adept Power Points AND Magician metamagics available, it's going to be quite a list!)
ii) Raising your Magic attribute (duh)
iii) Skills. Since you're a Face you need solid social skills. However, by the necessity of your other choices, you will be placing a VERY low priority on skills starting out.
iv) Spells, and likely a Mentor Spirit (choose carefully!)
v) If you manage to get ahold of Foci, you need Karma to bond them to you
Good news for you: Outside of acquiring magical Foci, Shamans are very cheap to build (nuyen-wise), which means you can put most of your income into magical security (remember to share with your team if they need a place to duck astral-tracking!), and equally importantly (as a Face) CONTACTS. With a CHA of 5 or 6, you have a pretty healthy pool of Contact points starting out, and should be just as important as choosing your spells.
I cannot stress the Contacts issue enough; I've lost count of how many times having the right Contact with a boosted rating has saved my bacon (mostly in SR2+3, but I suspect SR5 is no different).
Since your Essence is at a premium, an Awakened-friendly doctor (corp or street doc, if you can somehow find one) is a must. Without one, you risk permanently losing Essence to bad fights.
On that note: I'd personally avoid sacrificing ANY essence to Cyber/Bio-Ware starting out, unless there is a piece of sweet tech you simply cannot live without.
Every point of essence you shed puts you closer to Burnout, with each new point lost being more painful than the last (especially as a MystAd where your Magic score pulls double duty).
This is especially relevant in the long term, as you may lose some essence incidentally as a consequence of a really bad fight, poor health-care/recovery, or prolonged exposure to all manner of nasty environments (if the GM considers that in Lifestyles in the setting; I know I do).
By keeping all your starting essence, you have a better "buffer" against long-term loss of effectiveness.
Hope that helps a bit, and wasn't too rambling or redundant!