My first recommendation would be to have your endo get in touch with one of the larger LGBTQ centers that specialize in HRT for trans folks. It's great that she is on board to help and try it out, but she may need help figuring out the hows/whats/whys that are easily explained by someone who's been doing it for a few years.
Unfortunately, there is really no telling what T will do to you and when it will do it. Vocal changes occur over time - so if you were on for a short time, your voice may not get as deep as it would if you had stayed on for longer. Go take a look at any of the guys on YouTube who have been on T for over 5 years - you'll be able to hear definitive changes from pre-T to 3 months, to a year, to 2+ years, etc. Speaking personally, my voice started to drop within a week on T and dropped several more times over the course of my first year on it. I haven't noticed any additional deepening for a few months now, but that doesn't necessarily mean it's done. This is different for everyone though. I know I've read from some guys on here who are not happy with the way their voices have changed (or not changed) on T over time.
As far as hair loss goes, I've heard the general rule of thumb is to look at males on your mother's side of the family and that is typically what kind of hair you'll end up with. If you have brothers, they may be a better indication. I haven't experienced any hair loss on T. It's gotten darker and my hairline has changed, but that's about it. This is very similar to what I've noticed in old pictures from my mom's side of the family, so what I've heard is fairly accurate at least in my own case.
Like Dex mentioned, muscles are easier to gain on T but could be lost if you don't maintain diet/fitness after you're off. Fat would also redistribute to a more female pattern. So if those are important to you, it would be much more important to remain on T.
So it really comes down to what is important to you. I generally can't in good conscience advise people that T is right for them if they couldn't handle getting all of the potential effects and side effects. So if going bald is not something you could handle, then I can't tell you that T is right for you. Low dose or regular dose, it doesn't matter - there's no guarantee what it will do for you and when. I started on a low dose and got just as many changes as guys that started on a full dose.
But if your voice is the one thing keeping you from passing, I would maybe give it a shot? Start on a low dose and record yourself/take pictures daily so that you can see what changes you're getting. I feel like based on most people's accounts of their transition that I've read, vocal changes typically outpace hair changes. So maybe you could get to a point where you feel good about your voice before much or any hair loss occurs.