When I was working on Walkabout, I divided the population into seven different cultures who each survived in the post apocalyptic wasteland via different means. I had scavengers, neo-tribalists, farmers, mutants, vehicular nomads, skyborn drifters, and hermits in their surviving glass/steel towers. Each of these were divided into four/five castes, defining the various character roles that would be necessary for a community to survive in the indicated manner. The same sort of system could easily be used to describe the cultural diversity in this setting.
Scavengers are still scavengers.
Neo-tribalists are still neo-tribalists.
Farmers might exist on the open parts of the hive but are more likely to be focused on the various methods of cultivating fungus, and the imported creatures (lizard farmers, rat farmers?).
Mutants tend to exist in the innermost parts of the hive.
Vehicular Nomads are less likely to exist, but could be replaced by merchants who follow specific trade routes.
Skyborne Drifters certainly wouldn't exist in this setting.
Hermits in their glass/steel towers would be replaced by new arrivals who remain locked hermetically in their crashed astral ships, trying to avoid the fungal infections, or desperately clinging to the hope that they might be able to return home.
In Walkabout, there are a few organised alliances of towns, but for the most part each settlement is a self contained group of survivors with their own issues. A few are involved in feuds with their neighbours, a few are incredibly isolationist, most are interested in survival as a priority (whatever that means to them).
The Darkhive is pretty much a post-apocalyptic sci-fantasy setting, so the analogues fit. Since I'm most familiar with these themes, it's hardly surprising that they inform my design process once again. But I'm not trying to simply redesign Walkabout as a variant setting. Next week I'll be meeting up with local aboriginal elders, and I'm hoping to learn from them (Leah met up with the ladies group a few days ago), so Walkabout is back on the cards as it's own project.
For Darkhive, I'm actually pulling the idea I introduced for cultural descriptions in the last worldbuilding exercise. Each culture will have 13 elements that define it. Those who follow all 13 elements will be stereotypical paragons of the culture, most people will vary from their culture by one or two significant elements where they follow some other culture they've been exposed to. It's a bit of a reverse to the racial development system (where we start with a blank slate and build up traits as a character reveals their affinity to a specific genetic heritage), instead we assume a baseline of a specific cultural upbringing and deviate from there as a character is exposed to new influences.
A Language most commonly spoken
2 Valued Possession
3 Type of Clothing Worn
4 Valued Concept
5 Common Pastime
6 Housing Arrangements
7 Primary Virtue – strives to do this
8 Secondary Virtue – strives to do this
9 Primary Vice – strives to avoid this
10 Secondary Vice – strives to avoid this
J Religious Beliefs
Q Acknowledged Authority Structure
K Unusual Cultural Character Trait
(It would be tempting, since the critical characters in this setting tend to be female, to swap out the secondary virtue and vice for things like "hairstyle" or other girly things...but this just isn't that type of setting, and it would compromise the stories to go down that path. The majority of these cultural elements are about how the character lives and what they aspire to...not what they look like.)
There are two ways I could develop these lists of cultural elements. The first would be to create a list for each genetic heritage, implying that these were the cultural standards of the group before they became stranded in the hive. The second would be to create lists for the largest communities in the hive, working on the assumption that a large enough mass of people would stabilise their community around specific cultural norms, smaller communities regularly trading with such large groups would tend to adopt the cultural traits of their neighbours to facilitate easier trade. It might be a nice complexity to use both systems... An individual character starts with a baseline culture applied through their community of origin, if they start acquiring genetic traits from a specific race they start picking a number of cultural elements from that race implying their affinity with that group of people.
Actually, there's a third way I can develop a list of cultural elements, and that's to go back to the Walkabout survival methodologies. Since there are 13 elements that define the values, appearances and traits of a culture, maybe a character starts with a random hand of cards; where each heart indicates a cultural value aligning with the character's genetic heritage, each club aligns to their local upbringing, each spade links to their survival methodology, and each diamond is a wild card where the player can decide. Areas where one genetic heritage (or one survival type) dominates would have local values the same as the genetic values, and thus these would be predominant (characters of predominantly Nullan/mixed-heritage would default to local cultural norms). There seems to be something heading in a direction I'm happy with, but more thought needs to be applied.
There are currently 6 major towns, 9 races (including a catch-all category of outsiders who have recently crash landed and who haven't yet been assimilated into the wider community), around half a dozen survival methodologies (again including isolationists still trying to remain sealed in their ships as they attempt to escape)... that's over 20 lists of cultural elements to generate for starting characters to deal with, and there will be more lists of elements for specific secretive cults and groups to whom a character must belong if they want to advance in certain ways (but that's long term play). I might even generate up a simple system that allows a GM to create their own sets of cultural elements for small, of-the-beaten-path villages and towns.