1 - don't even mention what you are. It doesn't even matter. (Well, it matters to the people who will try to invalidate your opinions based on your ID, so fuck them. You don't owe them that information.)

2- sis, this is long. I wanted to read it, I was excited to read it, but even my eyes were glazing over, I couldn't get through the whole thing.

3- remember your audience. I don't know where you plan on sending this open letter to. If your readers are pre-disposed to siding with QT+ and disregarding anything a Terf-ette says, you're fucked. No ones going to read it, they're just going to gather around in a circle and wank on it. If your readers are pre-disposed to siding with LGB and Women with an E, then make it real easy for them, trim this down to no more than 1500-1750 words (and honestly, even less than that is better.)

4- It looks like they have a lot of race stuff going on, black, indigenous, latino, but the people who read this will try to twist the imaginary (hidden intentions behind your words) and make you sound like a "racist Karen" who hates black people or whatever. You going "here is another black thing, which is awesome!" isn't really helping, people are just going to be all "Nobody needs your approval, Becky." They will be looking for things to crucify you on, and this race thing will be super easy for them to do. You might want to consider not mentioning the race stuff at all, beyond saying something like "a very welcome diverse cultural enrichment of awkward euphemisms people say when they're trying to be performatively positive about race stuff like fucking voodoo that has fuck all to do with LGBT." But... yeah, in your own words. Don't single out the voodoo because "das wacist!~" unfortunately.

5 - I wouldn't focus on what-all is going on, especially because it's taking up a lot of space, I'd focus more on:

a) lack of LGB

b) lack of women who identify as womEn

c) do include those percentages you calculated.

d) consider using bullet points, especially to break up the wall-of-text feeling

Because we already established that this is a 7 day event, people will be able to do the math without you listing all the non-lgb/womEn events.

6 - you go off into a huge tangent about internet drama and terfs and whatnot. Again, I'd urge you to consider who's going to be reading this. Are these people fluent in tumblrese? I think of your thesis is "Pride MTL - gender identity vs sexual orientation - why can't we have both?" then you really need to tighten this open letter up, and cut out all the fat. The portion about internet stuff is really not needed.

7 - I think you might get more traction if you wrote this from the point of view of just a concerned citizen who is just innocently confused by the lack of LGB at pride, and the lack of E in womxyn, than as "I am TERF hear me roar!"

8 - I know you want to slay multiple dragons all at once with one open letter, but if you focus on these two points, I think you will have a better chance at getting heard by people who actually have the power to do something.