I realised something major about the Tau (and 40k as a whole). It has to do with what the various factions of the galaxy are doing back on their planets while the war rages on everywhere else.
So, we already know a LOT about Imperial civilians. They live on hive worlds, forge worlds, agri worlds and other such worlds or even on interstellar spacecraft and space-stations. Their lifestyles can be as hard and merciless as a Underhive Wretch or Forge World Labourer, or as luxuriant and glamorous as a Rouge Trader or Noble. We also know that there is a heavy commerce system (capitalism having survived into the 42nd millennium) and there is a massive black market for Xenos technology, strange artefacts, heretical items and pretty much every other mundane thing which is usually too overpriced for the common person to purchase.
The Eldar (at least the Craft-world variety to my knowledge) still have a civilian body aboard their massive city ships. Civilian Eldar are like really, really messed up versions of the Elves from Lord Of the Rings. Or perhaps Christopher Paolini's Eragon books. They practice some forms of music (mainly so they can fix their ships after battle by 'singing' the gaping holes in their city closed), and they are known to occasionally (like every 5 years) put out new technology for their battles (in the form of GW releasing a new model every few years or so. (The imperium gets all the good toys, while we xenos wait 5 or so years for a decent model to be released. Unfair anyone?))
As for the Orks...does anyone remember the brewer Orks??? The fluff ones who made squig lager??? Or the Ork women from 1e??? Yeah...I wasn' around then. But I still know that stuff!!! I guess the orks have commerce (teef) and they also have culture (beat up everyone when you ain't fighting anyone else) and they have a government (Oy!!! I'm the bigga boss, so shut up an' lisen ya zog!!)
The Necrons have sentience, but they really don't have civilians. BUT that is OK, because its due to the fact that they don't have a need for one.
Chaos is too busy infecting each other/having weird BDSM sex/turning into those-that-shall-not-be-named-for-threat-of-turning-into-one-of-them/Killing things in gibby gory ways/planning everything/failing to actually conquer anything through numerous Black Crusades/etc to have a decent civilian population. Though if they did have one, it wouldn't be very safe or very cheerful. Probably best not to talk about it....
As for us...we don't get featured that much in the Black Library fiction. At least not in depth. Yes, there has been a few good examples of Tau being explored (the excellent Farsight novels that just came out) and there has been some awesome stuff in the codexes and FE supplements, but we really don't know much about Tau civilians. The Tau definitely have then, as we have to outsource our population onto new septs and orbitals like this one. We definitely don't have many Fire Caste civilians (due to the only ones not to fight being those who have served as a Shas'O and retired with honour. When Ethereals retire, they are most likely euthanised. The Air caste don't like being in planetary gravity, as they have adapted for outer space over the years spent up there. If they do have civiliains, they would be aboard one of the orbitals. The most likely candidates for civilian populace are therefore the Water & Earth Castes. The water caste is a bureaucratic caste, but there wouldn't be many of them catering for other lesser Water caste. I'd imagine that they'd mainly be desk jockeys doing paperwork, or bean counters counting the empire's resources. Earth caste civilians would probably be research scientists or factory workers. As for commerce...we ARE called Space Communists, but I'd imagine there would be some form of working pay so that the Water Caste bean counters could track productivity, and so the lesser ranked caste members could have something to look foreward to as a boost to productivity. I'd imagine there would also be some form of government-approved media service, boosting morale on the home front via 'real' video footage of Shasserra's campaigns.
But all of this is just conjecture on my behalf. What does the community think???
Igne vir renovatur integra