I will explain my understanding of the answer. I do not claim my answer is the right one, but it is what I see.
Let’s say there are two groups. One group we will call a marginalized minority and another group we will call the majority or dominant group.
The answer is not for the marginalized people and the dominant group to debate directly. Imagine people from the black civil rights movement debating whether or not they should be guaranteed the right to vote with no interference. What really was there to debate?
Instead of direct debate I see it like this. First, both groups recognize their position. Trans people have been marginalized by a broadly cisgendered society. If you learn a little bit about the murder of trans people throughout the last 5 decades and the lack of investigation, I think that is evidence enough that they are a marginalized group.
Okay so step one is recognize the power dynamic. Step two is for the people in the dominant group to listen, without challenge or debate, what the people in the marginalized group want.
Step three: the people in the dominant group discuss with themselves how to make those changes. How do we make sure trans people feel welcome and comfortable in bathrooms and sports? How do we make sure trans kids grow up feeling welcomed by society as their whole self?
Fourth, the people in the dominant group discuss their difficulties they have with the changes, and they do their best to work it out on their own.
Five, some members of the marginalized group who have agreed to discuss this will talk to people in the dominant group and try to address their questions.
Six. Having made some changes, the people in the dominant group ask for feedback, and the process repeats.
At no point in that course of action do random members of the dominant group need to discuss these changes with members of the marginalized group. As a white person I simply do not challenge what people of color say. There is no need for me to challenge them and I recognize that as a member of the dominant group it could be emotionally distressful for them to have to discuss it with me.
Anyway that’s my answer. I hope it helps. Sorry I didn’t answer the rest of your post but I found this the part that felt most salient to me.