I am actually making a large part of my mod a tribute to Fallout Tactics lore because I think is a shame to just ignore such a good source of history, even if Bethesda only considers it semi-cannon.
Based on what Scribe Rothchild said in Fallout 3 about them being in 'Chicago' made me doubt people at Bethesda had even played the game, because regardless of which ending is cannon, the 'Minority Faction' of the Brotherhood of Steel ended up with their base in Colorado with almost nobody left in Chicago and that being by far the furthest place away from their headquarters.
I personally would never trust the Calculator, so I would not give it my brain and am die hard a follower of the 'destroy the Calculator' ending.
As a result though, the 'Minority Faction' is spread very thin across the Midwest. My personal view of what happens next is that they start to lose their identity, with letting tribals, ghouls, and mutties join, soon much of the Brotherhood has priorities that they hold more important to them than their Brotherhood duties. I can see the members of the Brotherhood setting up across the Midwest, starting families, and then wanting to stay with their family and protect that settlement as opposed to being all gung-ho about the Brotherhood.
So I would imagine 90 years later they have mostly dissolved into just local defenders who may wear the old power armor, but the centralized force is no longer intact.
According to my research, Cheyenne Mountain is now part of Legion territory, and if I remember correctly someone in the Legion mentioned fighting Brotherhood out East. I would imagine that 90 years later they no longer hold a centralized HQ at Vault 0, and what remains of the 'Minority Faction' is now spread across Kansas and Oklahoma.
Based on my story, 'Dagger Squad' a tribute to the squad that tool Vault 0 with the player, is out in Kansas and ends up setting up camp at Vault 54. I also have 'Talon Squad' which is at Tinker Airforce base in Oklahoma City, where they have been attempting to repair Vertibirds.
The characters in my mods are decedents of the characters in Tactics. I did break the number one rule of lore though, and I gave the player character of Fallout Tactics a name... so that might offend some people... But it seemed to impersonal not to.
So Maria Barnakey, who is named after her grandmother Maria Barnakey the wife of General Simon Barnakey is mother of one of my characters. This character actually references the whole robobrain thing and has Barnakey's locket as part of her apparel.
Another character is the great grandaughter of the main character of Tactics, but has the last name Dekker, because her father was a decedent of General Dekker.
Another companion character is actually the Calculator robot that kidnapped the already kidnapped Barnakey from Gammorin and took him to the Calculator. He tells tales about fighting Gammorin and surviving and having taken a rocket from the player character during the battle of Vault 0. He ended up joining the Brotherhood after being repaired and is now a Paladin General.
An east coast muttie who picked up the name Gammorin and is leading the survivors that had at one point joined the Brotherhood of Steel during Tactics in the task of finding a cure for super mutant sterility is one of the villains of my mod.
And the Reavers... well, they are the main faction my mod is centered around.
I am mostly a 3d modeler over anything else, so I am in the process of making new versions of the Tactics Power armor, there will be multiple versions, as well as the Humanoid Calculator Robots, Robobrains, and a Pacification Robot.
So I am not bringing back the 'Minority Faction' of the Brotherhood of Steel as a faction, but if someone is up to doing that I am very much willing to help out and share everything I have for my mod. I just already have too much going on with my mod to go large scale with my ideas for bringing another Brotherhood squad into the game.
If anyone is interested, I would be happy to send you a link to my website where I have all my stuff in progress.
Also, I never use the term 'Midwest Brotherhood of Steel' because it was never actually used in any Fallout game and is just a fan label...