I don't see CR having any conflict with KNF as the CR are way too busy fighting the OC and destroying Cardamine. I don't think CR has any interest in Kusari whatsoever.
As for joining KNF ... i don't like being part of any of the house lawful factions as they tend to be overly aggressive and way too quick to kill kill kill. Maybe when they tone down a bit and build up their "wars" I might consider putting in an app for KNF. There's supposed to be a war between Kusari and Bretonia and between Rheinland and Liberty ... um ... don't see a whole lot of battles. Just a lone Rheinland ship wondering into New York once in a while.
Lets actually see these wars in action. LPI and LSF can concentrate on the pirates and "minor" fights while the LN and LNS fight with Rheinland. Same with the other house police and militaries. Seems the military is concentrating way too much on domestic issues and not enough on the "war" effort. I'm not really seeing much "war" between the houses right now.