The setting is interesting. Jim's story telling is also interesting as he has managed to nearly avoid any form of exposition regarding this world leaving it all up to us to infer it from the narrative.
I think that "steam punk" is also a misnomer. Except for some ships having steam engines, and very few at all in this book having them, there was a distinct lack of steam. Except for the goggles, clothes and social setting, there's not much in common with most earth-based steam punk I've brushed up against.
It's not just meat that's grown in vats, but the crystals too, who knows what else is grown in vats? As posted above, it seems like it's just big blobs of boneless meat with a leather casing.
The various levels of the spires are called "habbles" (sp?). It seems that you have huge spires built to allow people to live off the surface of this planet. I would conjecture that the habbles are the habitat tiers of the spires.
The warrior caste are genetically modified. Possible the cats were too. (If someone wanted to give cat enhancements to humans, why not give cats human like intelligence too? For proof of concept, or because they could, or because the mad geneticist in question was a crazy cat-person who wanted their conversations to be more meaningful...)
Probably this planet was colonised. Genetically modified plants and modifying your live stock to not actually need to graze, or poop or move sounds good for a colony ship, and later on this world where the ground is not very hospitable. For some reason, they've back slid, maybe they're not quite neo-barbs, but they're a shadow of what the original colonists were...