I'm writing a hard sci-fi novel (unfortunately, using my native language, and it's not English. But I hope one day I'll translate this novel to English)

The novel lies on the intersection between a love story, hard science fiction, social fiction/post-apocalypse. I've created, I think, a very complex world, with it's own history, culture, weird and rational traditions.

But I hope, I'm not doing a lot of mistakes in the hard part of the science fiction. Despite I made my homework, I just want to check things here too.

Could you pls comment my assumptions? And if you think, they're wrong, could you please help me a bit modify them to make them more solid (I use these assumptions in the plot, etc)?

1. In the world of my novel, Mars is partly terraformed. Mankind used SF6 (as super greenhouse gas) to warm Mars up. As a result, Mars lost CO2 in its South polar cap. Additionally, terraformers used factories, which warm up soil, to produce even more CO2. As result, the pressure on Mars in this setting went above Neil Armstrong's limit. So, people can just go out without using space suits and complex EVA procedures, they just need an oxygen Mask. As far as I understand, CO2 in the South Polar cap is not enough to produce a required pressure, am I right?
2. SF6. In the setting, it tends to gather in the lowlands. So, lowlands are significantly warmer, than high lands.
3. Mars has very strong winds after partial terraforming, because of high temperature gradient between SF6-covered and non-covered areas, especially between hemispheres (South is generally higher). Winds are season-dependent.
4. People in the lowlands can easily build and use airships, despite pressure is not high, because SF6 helps them to let airship fly, and because pure H2 balloons should be safe on the Mars. The only problem are season winds.
5. There are seas and rivers after ~800 of Earth years, and Mariner Valley has a super river. It's a result of permafrost melting. But the areas, which they cover, are small.
6. Sand storms are changed: they're mostly local, in the areas without SF6 (and here they can be dangerous and catastrophic! Because of higher pressure, stronger winds, and low gravity), and in the areas in the low lands, vapor in the atmosphere prevents severe sand storms.
7. There are strong polar winds, really strong, and dangerous. Time to time they can leave polar areas
8. Low lands can temporary lost their SF6 caps, in a case of strong wind. So, it can be very-very cold during winter, night and in a case of polar wind reaches this area. This area can even lose it's pressure, if CO2 starts to condensate from an atmosphere as CO2 snow.

9 In the setting, mankind died out on the Earth ~800 Earth years back. It's reason, why terraforming not finished - and Mars society collapsed. Mars has The Great Ring - it builds from high-temperature superconductors, and produces an artificial magnetosphere. As power source, it uses fusion plants. When society collapsed, each sector of ring became an independent, kinda of feudal state, which has about zero international trade in it's GDP: each sector mostly has "natural" economy.

1. The world experienced technological regress. Mankind lose a lot of knowledge and technologies, not essential to survival. I can share list of technologies, which they lose and which they still have later. Just wanna let you share your ideas, don't want to interrupt you: please share it. Overall, I see it as a crazy mix between disel-punk and even steampunk technologies with an advanced biotech and neural science (each person on the Mars, for example, have a neural chip. They're much more primitive than they have in a time of social collapse, but still can do this). Also, each human has a computer, implanted in their arm - to support by computing power primitive neural chip. This computer build using technologies which are close to, I think, ~1999-2010 years or so.

2. The heart of local economy is fusion plant. Mankind no longer can build other plants like this. The trade league(I'll tell about it below) can build fission plants, but nobody use them, because fusion is much better. How to explain, why these plants still work?

3. because it's difficult to capture a fusion plant intact, you can't invade another sector, but not it's cold and dead ruins, Mars has no major wars. Warlords usually just perform rides, to capture new slaves. The only major war, which recently happened, is a war between Trade League and one of sectors, to control uranium deposit (unique in the plot, and locates close to hellas planitia)

4. there is trade league. They're performing nearly-dead(in terms of money's value) international trade. They use electrical rovers, which can be charged from a Great Ring, to travel between sectors. They mostly sell or buy ancient artifacts, or sell services, using these artifacts. Example: robot-surgeon, which can transplant brain, and an artificial womb, which can grow up a GM-modified custom body. They don't have any money, they use barter.

5. There are high lands, during Trade League trips, and pressure there is so small, which requires pressure suits - very special locations for my plot

6. People are mostly live in the big metal's barrels. Living conditions are harsh. But trade league had two comfortable domes, survived during social collapse. One of them was destroyed in the nuke blast, during first major war on Mars(and it was started by Trade league itself). What do you think about these domes? Could you please describe how they can look like? Which technologies they use? How big they can be? In the plot, I expect, there are ~50 or so small domes, connected to each other, and this city is home for ~5 million of Trade league employee (and among of them are most educated scientists, engineers which live on Mars at the moment)

7. People are often use fluorine fuel cells (which also use CO2 from atmosphere). Local factories produce them, and use in the power armor, in the blimps, etc.

8. Jet engines and planes are rare, but Trade league has few sub-orbital rocket, which uses ramjet fluorine engine, which burn atmospheric CO2 in the fluorine. Existing planes are use turbofan fluorine engine. It's actually lost technology - mankind were able to build them about ~200 of Earth years ago.

9. The Sector's elite are immortal, they take anti-aging pills. Good performers among Trade League employee immortal too. Slaves have a very short lifetime. Bastards don't permitted to take anti-age meds. Why is that? Because society can't grow, because it's impossible to build another fusion plant.

10. They have pan-Martian Olympic Games. Elite use it to spread patriotism in the sector, and.... To reduce amount of men among elite. By Olympic rules, it's possible to have not more than three survivors each game: who won gold, silver and bronze medal. Everybody else should die. Also, men among elite can finish their initialization, and officially become an adult man (not a teenager anymore) only if wins one of medals. It helps to keep the amount of men among the elite small. New game happen each ~25 Earth years. Trade League is moderator and organizer of these games.

11. There is no social mechanism to limit the amount of woman among elite. And it will cause a social collapse, which nobody expects.

12. Sectors use bastards as solders and cannon's meat, during rades against other sectors - it let them keep amount of male bastards low. Their children can become elite, if they marry with a woman from elite (it's recent changes in the traditions...)

13. Girls among bastards usually have a career as specialist, and usually not marry and don't have children. And their children, if they're not a wife of a man from elite, born as slaves. And they're often less beautiful, than women from elite, because women from elite not aging.

14. Trade league sell educated slaves-specialists: they're special caste.

15. People wear suits. I've created a special system, traditions, for their clothes. Example: slaves wear suits with stripes. Male elite members wear red-black military camouflage, and females from elite wear suits with prints, which they choose (like photo of tree, or maybe an ancient photo of Earth from the orbit, etc)

16. There is life on the Mars(with Earth origin, of course). Mostly bacterial, and the most complex organism is lichen. There are Spring Lichen's spore Clouds: they're have red-green color, which can be different during sunset/sunrise, and Mars society have traditions about that time - time of observing lichen's spore clouds. It was a plan, to spread more complex life, but it was halt during social collapse.