Judging by era report 3145 it doesnt sound like spirit cats are taking nova cats after kev rosse died.
Era Report says that they refuse the message to return to the fold and stick to themselves, not that they turn away any incoming Nova Cats. Remember, although they call themselves Spirit Cats, they still consider themselves Nova Cats. In
To Ride the Chimera, the delegation Rikkard leads to Oriente is called the "Clan Nova Cat Delegation". If a bunch of Nova Cat warriors and other castemen showed up over Marik one day, I feel like they would be accepted.
Also,
Roosterboy mentioned that the Spirit Cats accepted the Nova Cat enclaves located in the closer Prefectures of the Republic to them (VI, VII, VIII), so there's no bias to other Nova Cats. The Spirit Cats just wanted to go their own way; the Nova Cat alliance with House Kurita was a dead end.
I wouldnt worry about the genetics. They have scientist castemen. Their doctors are present in the novels and they have the clan that built most of the genetics equipment on world with them.
True.
The Spirit Cats followed their hearts, just like Nova Cat tradition emphasizes. They're something different now, which is fine. Given their size, I could easily see the Spirit Cats getting subsumed into the Sea Foxes at some future point. They're feisty, but their size keeps them reliant on the Foxes for a lot of infrastructure, as well as acting as a brake for bigger powers trying to take them (looking at you, Alaric). I'm not saying the Cats couldn't survive if given enough time and support, but as fast as things are changing in the current timeline, it makes me wonder.
From the picture 3145 paints, the Spirit Cats are doing most of the heavy lifting in the Clan Protectorate. They staff the Protectorate Guardian Clusters with almost all the officers, they hold Marik as their own planet outright, etc. The Sea Foxes meanwhile are mostly concerned with the trading aspect in the Protectorate. Furthermore, with Rikkard and Petr's 'friendship', I don't see an absorption as likely.
Kev Rosse's original goal with the Spirit Cats was to return them to something closer to what the Nova Cats once were; an independent strong Clan that followed its visions. The Clan Nova Cat of their day was largely vision-less, dominated by the Kesari faction, and holding onto life on reservations guarded by the Draconis Combine. The Spirit Cats are essentially a return to the old, although they did become a part of the FWL, which might violate Kev Rosse's original precept of making no alliances with Inner Sphere powers.
