1) The Kusari Civil War is dead for several months indeed, and work has begun on its conclusion, both in terms of rp and development. The issues of Empire vs Republic, Kishiro and Samura however are not things that can be casually cast aside, for they are all based and rely on the current scenario. Careless disregard or retconning would have Dire consequences.
2) Perhaps with the recent forum advances in terms of messages and rp, the Gallic war could end it's current chapter with the Bretonian arc finale. Not my place to say it would be based upon the capitulation of Bretonia capital, or a general rout of the Gallic forces in the south theater. Up to other people, other dev channels, other factions.
3) Kusari is not divorced from the conflict against Gallia. For years the EXILES (IKN) was based on the Taus and was just another CR and Council like resistance force against Gallic military everywhere from Edinburg to Kyushu Gate. Right now, with their holdings in Kyushu more secured, the players of IKN can still under their ID harass Gallics pretty much over all major lanes in the Taus, as well as Rishiri, if I'm not mistaken. Strange no one is trying that.
There is a House Military like faction fighting inside Gallic Space, it's called the Gallic Council. Don't see indies or others throwing capitals against Lyonnais or Duphine, don't see why A Kusari faction would be a game changer.
4) In terms of inrp, no, nothing of note. Otherwise, how would you justify having a crippled Nagumo still in Kyushu, hiding, if KNF could planetdive 6 Tokugawas against the IKN positions?
Outisde of the story, there have been the cultist incursions, the catastrophic Kyushu Nomad Invasion (which almost triggered a Gallia/Kusari lolwar), and the Gas Miner 18 skirmish in Sigma-19 this past month (even though we weren't specifically invited for that).
If Valors are dormant, is either their owners are too busy with real life, or Liberty/Bretonia tactics have become a dull challenge. Perhaps (perhaps) KNF may be less inclined to tolerate GRN forces so close to home in the future, but before that you should and could improved CR, Council, and whatever shoots Gallics in Taus first. If lack of shooting Gallics is a current issue.
The voice in the back in my head uttered my first reaction to this idea. "What a convenient idea to present now, when the Sigmas are getting busy (but at the same time, not getting busy)."
Here's another radical idea: have Kusari declare war on both GMG and Rheinland, and claim Saigon, Miura, and Hammersee. Because what the heck, it would be "because it'd be good for the mod." If Kusari can be bold to take one, why it should refrain from the other two?