Firstly, the physical symptoms, by themselves, are not significant or diagnosis of something. I mean, people regularly dismiss my claims to intersex and everything besides my shoe size is smaller than you (I wear women's 9, or men's 7). However, it can help provide a bigger picture, in addition to other, more important things. In itself, wether IS or not, it's also a big help in passing.
A karyotype, of sufficient sample (to find out if it's XX, XY, XXY or something else, or mosaicism, though that's actually hard to find out, though possible).
Blood test levels, estrogen, testosterone total, testosterone free, luteinizing hormones (LH), follicule stimulating hormones (FSH) levels, presented with min-max scales (611 T level doesn't mean anything in itself). All of this pre-HRT of course. The karyotype can be at any time, they're not known to change.
Voice is anecdotal (to go back higher), and especially for your age, you're only 16. So don't bet this on it proving anything.
Anti-androgens are supposed to diminish body and facial hair or at the very least soften it, and since you're still very young, it could even eliminate some (I seriously doubt all, unless you have very very little to start with). But having androgen-type body hair and facial hair at 16 is far from uncommon. Not having any before early 20ies is seen as 'just not the norm, but not in itself a symptom of intersex', though some intersex people do get facial hair young - it all depends on the condition, the individual, past treatments, and what not.
AIS is a possibility, though, being as young as you are, you'll have a hard time convincing a doctor to look into it. AIS is tested by tissue response to testosterone, if you've had trouble masculinizing (tissue response), while having normal or elevated levels of testosterone, FSH and LH, then AIS is a strong possibility.
If not AIS is a pretty slim possibility. From your details, I cannot judge your tissue response, though you'd have to qualify what your facial hair looks like as far as distribution and growth (meaning spread and speed of growth). If you can grow a full beard, your testosterone response is totally normal, maybe even above average.
XXY syndrome is a possibility, mainly because of your hips. Gynecomastia may be incidental, but could be a point in that direction. If your testosterone levels were low previous to HRT, XXY is a strong possibility. XXY syndrome is revealed by karyotype. Mosaicism involving XXY syndrome also exists (such as XY/XXY, XX/XXY, XXY/XXXY) and a more normative (less evident) form could be XY/XXY (its more male-looking). Note that although there is few information, XXY syndrome can affect phenotypical females, who are fertile and do give birth, as seen anecdotally (research olympics testing).
In the end, I propose you do not put too much faith in wanting the diagnosis for validation purposes. I want my own diagnosis to satisfy my ever-thirsty curiosity, and to know how I came to be the way I am (physically-speaking).
Sara
PS: If you want to talk or something, check my profile information for contact info. I can refer to a great deal of information...although I can't refer to docs, endos or other specialists...since I don't know many myself, and none with regards to this.