I'd like to suggest its effects on the Adeptus Administratum. Not only would the coffeetron have endeared the theoretically almighty organisation to Callamus, it would've also greatly improved productivity of the bureaucracy's adepts.
The Novus and the Old Guard
Colours: Blue and Dark Red
Known as the old arguments, these parties fight over differences in technological advancement. The Novus can be best described as equivalent to the Trust's progressives, although probably more extreme due to 1000 years of doctrinal progress.
They can be said to be the strongest drivers of innovation, reverse engineering of xeno tech and in general try to get away from the "outdated" traditions of the mechanicus as possible. While their success can be undeniable, they have also been responsible for some of the greatest accidents within Callamus as their enthusiasm gets away from them. However, without them the polity would have likely fallen as they have improved industrial production, weaponry and more without which Callamus would have fallen.
By contrast the Old Guard are best equivocated with the Moderates of the Trust. The views of the Old Guard can be best described as wanting to keep with the Old Mechanicus values and take the slow and steady path towards progress. As such they disapprove of innovating new technologies without the greatest need, reverse engineering of xenotech and the implementation of rediscovered technologies without extensive testing. Instead they prefer to send out expeditionary fleets to rediscover lost technologies. However, as the galaxy grows more dangerous fewer and fewer fleets are launched.
In general both parties are in a state of equilibrium with the Novus coming up with ideas and attempting to work on them, while the Old Guard tend to act as watch dogs, anticipating accidents and trying to shut down blatantly dangerous or foolish study, when such things arise.
I don't think this makes sense as written. Callamus' success has very obviously been a direct result of technological innovation and other Novus-endorsed ideas. The Novus and the Old Guard would not be in equilibrium, not unless the Old Guard had something equally as valuable to bring to the table, and acting as watch dogs on the Novus isn't enough. The only major discovery Callamus has made according to your omake is that of one kind of grav tech. That's it. That's not anywhere near as much as the Novus faction is implied to have done. From that, we can conclude that their expeditionary fleets are not and have never been useful enough to warrant gaining the same amount of prestige as the Novus.
There are two things I suggest crediting the Old Guard with so that they're on par with the Novus: prestigious explorator fleets and optimisation.
For explorator fleets, I mean things like going through hell and killing many enemies of Callamus to recover many minor but important technologies that would've otherwise been lost to humanity forever. It's materially useful by giving Callamus more tech, plus it'd make them popular because of how pious their actions are and because they kill hated enemies.
For optimisation, I mean optimising the use of technologies that Callamus has. The Novus are forward thinkers. They want to innovate, to create wondrous new technologies for the benefit of Mankind as the Ancients did. The past is something they'd see as shackles that hold them back. The Old Guard would be like the monks in monasteries in medieval times who pored over ancient texts in hopes of better understanding the universe. The Old Guard would see the past as the key to the future. Unlike the Novus, the Old Guard would be very interested in exploring and exploiting what technology Callamus already has to its utmost extent, and to uncover the secrets behind obscure rituals that look nonsensical but seem to have purpose. It's they who'd piece together the combination puzzle and cipher that is the Adeptus Mechanicus' technological base and create a whole that's greater than the sum of its parts.
The Almatia are "peace makers." Their beliefs are that the Mechanicus has been derelict in its duties towards humanity for tens of thousands of years, hoarding technology that should have benefitted all and is one of the ones directly responsible for the creation of the Abomination. In the Mechanicus their diplomatic skills are unsurpassed, as are their abilities in industry, creating phantom economies and ensuring creature comforts to the menials that make up the polity. However, they also serve a darker purpose, specifically as spy masters, keeping watchful eyes upon the menials to ensure that they do not fall to darker powers.
Doesn't explain why the Almita hold as much overt political power as the guys who are famous for killing xenos and heretics. Diplomacy is pointless, because the Forge-Empire has no non-hostile neighbours. Phantom economies and creature comforts are nice, but not that important. Spymasters are good, but that's secret, and wouldn't give overt political power.
To explain why they hold as much power as the War Makers in an age where there is Only (Even More) War, I'd like to suggest cleaving a bit more closely to what makes them so influential in DEM if you want them to be a powerful political faction in Embers. There, they're responsible for civilian life. Like, at every level. They're what allows for the highest tier of civil care, which translates to population growth, public order, surveillance, and, critically, education. They contribute a lot to the Quest for Knowledge because of how their efforts result in more people joining the priesthood.
Unlike the kind found within vehicles like the Land Speeder, this grav did nothing more than lighten what it was attached too, without providing thrust.
This is from Dark Heresy 2e.
That "rediscovered" tech already exists. Outside of Dark Heresy, I also remember seeing this kinda tech show up in Astartes weaponry, with similar tech being put into swords to make them easier to handle.
