Best wishes! Everyone starts at this point, and things do get better. Here are my thoughts:

1. First of all, I want to say being a lesbian isn't about how you look. One of my good friends is a butch cis woman, and she gets mistaken for a man all the time. That being said, I understand exactly how you feel. I identified outwardly as nonbinary for a long time knowing full well I was a woman because I felt like I "didn't deserve" to be a woman, much less a sapphic woman. Being on estrogen for a few years really helped with that, but the steps you make before that can go a long way too. Pre-HRT was a fantastic time for me to develop my voice, learn makeup, learn how to take care of long hair, and get laser hair removal. You list might be different.

2. I'm not autistic, but I hope you get some more good answers in this post.

3. I never really tried to suppress my femininity around parents while in the closet, but it might be a safety issue for you. I'm sorry if it is. But like JennyLaFae said, sometimes cis people can be really oblivious. Sometimes people would call me out for being too feminine, and I'd just roll with it and it wasn't a big deal. Otherwise, do you have friends you can be your true self around?

4. I didn't intentionally mean for things to turn out this way, but when I met my now-long term girlfriend, she was living in a large, queer-friendly city 90 minutes away from where I was living. So when the time was right after a few years, I packed my bags and we moved in together. The bottom line is that I couldn't have afforded to live comfortably in that city alone, so I found someone to live with. Which could be a partner or a roommate.

5. I don't know. I'm so sorry. It depends on what you're diagnosed with. Specifically for gender dysphoria, my therapist told me that I'm my own worst critic, to avoid mirrors unless there's something I specifically need to do, avoid comparing myself to other women (which for me involved quitting Instagram) and not to project how I perceive my appearance onto others. For instance, if I'm in public and feeling dysphoric, I tend to assume everyone's looking at me and thinks I look gross. But is that what they really think? Most people are so wrapped up in their own things that they don't even notice, or maybe they even think I look good.