I've been trying to establish canon just for the Alliance history pre 3300.
https://forums.frontier.co.uk/showthread.php/365538-A-history-of-the-Alliance-from-in-game-sources
It's tough.
The Milky way chronicles are good for a base timeline. But I tend to go back to in-game sources like these:
The FE2 Gazeteer: http://lotf.co.uk/fe2_gazetteer.html
Current In-Game Tourist Beacons: https://docs.google.com/spreadsheets...it?usp=sharing
FFE Journals: http://www.dream-ware.co.uk/first-en.../journals/all/
The FFE journals should be canon, but the problem is that they have been extraced from the game files, and so it CAN'T be established exactly which version of Mic Turner's death and the end of the war with the Thargoids is canon. It changed with the player's actions. For instance INRA at one point holds Meredith Argent prisoner and threatens to lock her away in Ross 128. But that doesn't happen if the player didn't achieve certain mission goals. And then apparently the ending of the game was bugged and you had to cheat a little to get across the line.
And then also in the FFE journals - each of the 'newspapers' was an 'unreliable narrator' where some were trashy tabloids and some had an obvious agenda, and some were written to amuse the players and some were written in earnest seriousness.
I've tried to work out which version best sits with current ED lore, but I don't think anyone could take this on and make everything line up neatly with how things are now.
According to one interview with Brookes, the mycoid ending has been retconned out - The Alliance never got a Thargoid SuperShip. But then other things around Mic Turner and Meredith Argent exist in-game. So in that interview with Braben where he says "There is so much rumour and misinformation about the end of he Thargoid war" he's saying that because Frontier themselves cannot establish a coherent set of stories.
I don't think there is a widely understood Elite History within Frontier. I would trust Michael Brookes before I would trust David Braben, and Brookes is gone to other projects.
Brett C should have a good grip on the lore, but he's got so much on his plate with hundreds of player groups trying to set up camp and push the lore around.
History is messy.
Especially ficional history.