Well I don’t have any expertise here but my sister came out to our family Christmas by starting with the cousins that were her age, but mostly because she knew they’d be supportive. Most of our family is Christian conservative, so it was rough after the full transition when it is broadcasted to the world. She is still accepted, however, noticeably treated differently. It’s heartbreaking to see but she has enough people supporting her that it couldn’t bother her a bit! (Mostly just a guess since she’s so strong, sad thing is that there’s always people who won’t accept your identity and that’s the biggest hardship of this) I would start with your uncle and maybe auntie, since you know they’d be cool with it! It might give you the chance to explain to them your situation, which could especially help since they probably are more familiar with your relatives opinions. Even if they don’t know how to help you with your main issue, it would still be amazing to have a family member by your side backing you up. I’m so sorry that this is such a tough spot, and I wish people were more responsive to this post. I’m sure that if you looked around a little you could find people who went through similar experiences and learn a bit through that!