I just recently came out to my mother, and coming out as non-binary is DEFINITELY even more confusing to a seventy 72 year old religious woman. So I completely agree with you that coming out as Non-Binary is trickier.
I am without a doubt non-binary in my mind, AND transmasculine. Am I a man? I have no idea yet. But I know I'm DEFINITELY way more masculine than feminine. That's why I identify as non-binary. I want male attributes so desperately, to use he him pronouns, but to deny femininity entirely feels wrong too. But when I come out to people, why some transfolk may say non-binary isn't really trans, especially if you don't transition at all, I will still say I'm transgender.
Trans just means, 'on the outside of' and then add the word gender. So to be anything outside the gender you are assigned is literally the definition. Cisgender means on the same side of gender. So you identify as the binary gender you were assigned. So while Cisfolks and even some transfolk might not understand that definition, calling yourself trans when you identify as NB is perfectly fine.
I don't particularly feel like doing so invalidates your identity as a non-binary person. Another thing to remember is your audience. Like my 72 year old mother... I said I was transgender to her, but then explained that I am still figuring out what that means to me, but I know it means I'm not female. Will I take hormones? Who knows. Will I physically change myself? Probably at least the top half. But non of that will change the person she knows, and that's really what matters.
And when you have an audience that may understand, then you can say something when they ask a question like, 'So you feel... (hold on, scrolling to see if you mentioned your assigned gender) female?' Then you can say, 'No. I don't. I fall somewhere in between, though probably more on the feminine side. My gender is non-binary.' Own it ... use the word non-binary for what it is... a gender marker like male and female. And then let them ask questions about it. Explain what you've said here. That you just don't feel like you need to fit into one of the binary genders. You're just being you.
As for failing the community if you don't disclose your non-binary status, you aren't. Its just a matter of knowing your audience when you come out. Knowing your own comfort levels. Knowing what's safe to say. Just like a person might not disclose that they were born a different gender when introducing themself to a stranger, or a non-transitioning person might not tell people they are trans at all.... None of that is failing their community either.
Also, agree with previous poster about presenting it in a medical format. I've done that myself to the people I've come out to, even online. Granted, I do feel like I'm transgender in a medical sense because I do have a gender dysphoria inducing medical condition anyway. Again, its all about knowing your audience and what you are safe to say.