We're not rewriting history. Allowing a transgendered person to choose a new name doesn't change the basic facts about what happened. It's just an act of compassion towards someone who would otherwise be suffering from feelings neither you nor I personally experience, but are well documented by scientists.
> Shouldn't it be "Bradley Manning (now called Chelsea)"?
You could say "Chelsea Manning (at the time, 'Bradley')" if you really wanted to refresh people's memories, so long as you consistently refer to her as Chelsea through the rest of the comment/essay/etc.
> I prefer objective to polite.
This is a false dichotomy. You can be both.
Yes! This book about nonviolent communication (https://toptalkedbooks.com/amzn/1892005034) talks about the ways people try to control one another, and a big one is intimidation. It says that if you call someone out on whatever their method is, it disarms them and they stop. This has helped me so many times in dealing with people.
Whenever I'm faced with someone who is yelling at me, all it takes is starting my reply with "it sounds like you're really angry about this" and they instantly calm down.
The people saying we can't help you with all of this are correct - some of this is about mediation, communication, and culture.
But some of it is about gaming, and we can help with that part.
First of all, from my experience it's important to choose a system and / or implied setting that won't inflame the parents. Kids won't have trouble with systems. I started w/ B/X D&D in the red box at 10 years old and it was fine - I started my own son at 7 with D&D 3.5 (not my favorite game even at the time, but the reasons for choosing it were sound...) and he did fine. What you have to worry about is probably parents. In the US, it was easy to run afoul of religious zealots who freak out about any hint of magic. It still is.
I'm not sure what the social conditions are where you are, you're the best judge of that, but I would direct you to Beyond the Wall It's inexpensive and has several free expansions but here are the reasons I recommend it:
It's designed to take new groups through a collaborative, guided session that generates a setting, characters, and initial situation that is unique and woven together from everyone's input. So they'll feel like they own the game and be more invested from the start.
It focuses on young heroes, barely more than kids, protecting their home on their first adventure. Probably something that this group can get behind.
It's mostly a OSR D&D-like game.
I recommend that game a lot.
In your situation, you might also like to look at Psi*Run. It was developed by Meguey Baker (D. Vincent Baker's wife and game design collaborator) for use in a teen RPG program at a library. It's meant to get kids right into the action immediately - they're super-powered teens (like X-Men) fleeing a force that wants to capture them.
Good luck with the rest of it. Oh - I'm not a counsellor or social worker, but you might want to read the book, Nonviolent Communication . It's got a lot of advice for how to deal with charged situations and long-standing bad feelings.
They aren't textbooks, but they do have information to learn in them.
Here are a couple of things on my reading list:
Why People Die By Suicide by Thomas Joiner
How to Be an Adult in Relationships by David Richo
Hold Me Tight by Sue Johnson
Nonviolent Communication by Marshall Rosenburg