Ask, and ye shall receive.
How many worlds are under the control of the Hegemony? How do the other factions compare to that?
The Hegemony all started with 5 core worlds, when it was established, and has grown a bit further since. I believe the exact number will actually be part of the begin-game randomizer.
How long does it take on average to reach a nearby world?
Well the distances vary wildly. It also depends on if the world is in the same star system or a different one. If one was travelling in a cruiser, on average it would take about five days to reach the nearest star with hyperdrive.
What are the main factions? We know of the Hegemony, Tri-Tachyon and the Luddites. Are there other big league players?
The Star Patrol, an elite group allied with the high echelons of the Hegemony, The Free Traders Guild, The League of Nonaligned Worlds, pirates, and so on
Is the Selenius system still independent?
This information is classified with a minimum rating of Planetary Clerk of Arms for view rights. Sorry!
The Luddites abhor technology, yet are not afraid to use it. Do they consider using technology to be a temporary measure? Do they believe the sector can survive at all without UAC's and autofactories? Can their society function at this very moment? Or are they just some sort of 'terrorist group'?
Use of technology is considered a necessary evil, and is only sanctioned by the Messiah, Hand of Lud or High Priests. According to their beliefs, the Sector will not only survive, but flourish if all technology is eliminated and humanity returns to an agrarian society. For proof that humans can function without the curse of technology, one need look no further than the Chronologicon, which describes a time of blissful utopia that existed on ancient Terra before the invention of space travel.
Are there still worlds that are being actively terraformed? Or is terraforming considered to be Lost-tech?
Terraforming is no longer taking place anywhere in the Sector, since the know-how has been lost. There are still some worlds that were being terraformed at the time of the Collapse, their biospheres being inundated with nanotechnology left without commands for hundreds of years.
Is there a standard template for an autofactory? Or do they differ in shapes and thus have hundreds of templates?
Not sure what you mean by a standard template here. But, in any case, the core component of the autofactory is the UAC interface which is able to somehow decode the data within and execute commands into the hardware servos.
Are shipyards considered to be a massive autofactory?
They are very similar, but naturally, the orbital shipyards are setup in a specific way to deal with the vacuum of space and with mainly producing ship's hulls.
Can new autofactories be constructed at all?
While it is possible to construct an autofactory doing so is a difficult task. Furthermore, the limiting factors for construction are usually the lack of raw resources required, and often, the lack of required blueprints.
Are autofactories the only way to produce things or is the sector reverting back to old school manual labor?
All manufacturing is centered around the autofactory model. This does not at all eliminate manual labor. Even within the manufacturing process, many laborers are involved with completing tasks that do not require advanced technology to complete. Like buffing.
Production is done by using templates provided by UAC's. How important are those to the 'tech level' of the sector? Is Tri-Tachyon doing research on its own for instance? Or are most technological innovations rediscovered instead of researched?
Research has a different meaning than the word as it is known to us today. Research, the one done by Tri-Tachyon and others, is a process that involves a couple of things. First, techmining, or retrieving Domain artifacts to locate blueprints or working components. Second, analysis deconstruction and\or integration. Lastly, potential blueprints extraction. That last step is extremely rare though.
Since Inferium is the sole source of space fuel, what stops the hegemony from dominating its regulation? Or is the source of Infernium far more widespread, allowing other factions to gather their fill?
Infernium occurs naturally in almost all matter, but the refining process is extremely difficult and time consuming. Hence, the Hegemony does not dominate this resource.
How is everyday power generated? Fusion, anti-matter? Do spaceships use the same powersource for everyday activity or is spacefuel the only thing that keeps a ship running?
Various power plant types exist. Which is in use depends on many factors, such as the technical support structure present, power plant blueprint availability, and market forces. The Chronologicon on the Epochs of Man, a definitive historical text, relates: "... power was produced differently during the Four Epochs, starting with chemical, fission, fusion, then advancing to plasma and eventually matter-antimatter plants."
How widespread is piracy? Are we talking the glory days of the buccaneers in the Caribbean? Or are the other factions capable of keeping their main lanes secure?
Piracy is pretty widespread. The only way we know to stop it is to humbly not include an extremely invasive DRM scheme, and thereby shame all potential pirates into actually buying the game, which will of ... WAIT THOSE KIND OF PIRATES!!! Hm, OK, still pretty widespread.
Are mercenaries organised in any way? Battletech for instance had Merc-Net, where everyone interested (and rich!) could hire a merc. Or is it more 'I know a guy' and visiting the seedier bars, thus making it more of a quest to find mercenaries?
Mercenary outfits exist, but it’s not as widespread. The reason here is that it takes a lot to run an entire fleet of ships.
Are there any notorious pirates or mercenaries? The IIS Black Star seems to be quite known for instance.
One of the most infamous is the dread pirate Kalgar Thrax, a cruel warlord known for his methodical extermination of captured crews not eligible for ransom. Another example, while not a mercenary, is Admiral Sonnel, a famous Hegemony flag officer and hero of many battles, most notably the epic, defining battle fought at the midpoint between the three star systems Fal, Gal and Tar near the Mediosolar Expanse.
Do they still have beer in the far future?
Humanity has been fermenting sugars for thousands of years. There is absolutely no reason Sector brewers would all of a sudden abandon their ancient and noble vocation. Cheers.
Is there currency in the sector? Is it universal and thus accepted by everyone?
The Sector-wide currency is the Domain Credit, or just credit for short. In the times of the Domain it was backed by the universal authority of the Second Economic Dictatum, which served to create the universal currency amongst other things. Post-Collapse, the Sector has failed to produce a financial authority that supercedes that of the Domain.
How is the chain command for the Hegemony? Do you have an admiral in charge? A leader? An oligarchy? Do they use contemporary military ranks?
The Hegemony features one of the most rigorously administered chains of command in the history of humanity, too complex to list here. As such there are many organizations within the all-encompassing Hegemony, such as the Administratum, the Engineer Concilium, and the Military. All of these are of course subservient to the High Hegemon-Administrator. As far as ranks, they mostly follow standard military ranks of today. The main division is the one between officers and men, with non-commissioned officers serving as well. Thus, an officer with the rank Commander may sometimes be the senior commanding officer on a ship (especially frigates).
Do the Tri-Tachyon or the Luddites use a similar chain of command?
The Ludii do not actually have a chain of command at all, just the Messiah and various High Priests. Tri-Tachyon on the other hand, is highly regimented, if not as sprawling as the Hegemony. The Tri-Tachyon military is commanded by the Chief Strategy Officer, who reports directly to the Vice President of War.
How are ships piloted? Is it the same principle like a bridge in Star Trek? Or do the Tri-Tachyon for instance use more fancy stuff like advanced computer systems and holographics, allowing for smaller crews?
None of the ships feature bridges like those found in Star Trek. Ship tech level is actually the determining factor, and the "how" varies considerably. After all, some of the ships flying together now were designed during different Epochs of the Domain, hundreds, sometimes thousands of years apart. A Mastery Epoch ship bridge has more the feel of a World War I submarine, cramped and utilitarian, even claustrophobic. Crew comforts obviously improved with subsequent Epochs, but it was never a huge design priority. Remember, only one of the ships currently in the game has an exploratory role, the Apogee-class. In Star Trek, Starfleet ships are mostly exploration ships, not warships (with the exceptions of ships like the Defiant-class).
How are captains, officers and crew trained? I imagine the Hegemony uses an academy or something, perhaps even just conscripting crew from the 'undesirables' in society. Tri-Tachyon might do more headhunting, since I believe that not every scientists is as 'adventurous' as a ship's captain. The Luddites perhaps just make do with eager volunteers. Something along these lines?
It varies considerably, as you might guess. Typically, core worlds that belong to a faction will serve as their primary recruiting grounds. For example, Hasteus Prime serves that role for the Hegemony, as well as being its capital.
How are marines armed? Do we have low-tech marines with ballistics, middle-tech with some laser weapon and high-tech marines covered in an exoskeleton? Or am I just going overboard?
Usually powered armor, with an extremely wide variety of personal sidearms and equipment.
Are planetary invasions commonplace?
They are rare nowadays, since the amount of resources required is so vast, and usually, there is so little to gain. Raids on shipping and planet-bound supplies are far more common.
EDIT: BTW, standard disclaimer on my answers above. Some of what I've said may change, specifically things related to gameplay. I am sure you guys are aware that it is still under development. Thanks!