ilKindraa = Uber Kindraa
That's all it means. The existing Kindraa have been on their present state more or less for generations. So when the Kindraa started teaming up, they needed a way to describe how these Kindraa had become "more than one Kindraa" and a new term was born.
For different reasons and under different circumstances they paired up. I wouldn't be surprised if some of those ilKindraa don't last. They each have been used to being in total command of their own destinies for so long, being subservant to another is likely to be chafing to some. But it really depends on the overall situation. If ilKindraa become the norm, then splitting off makes you appear as a suddenly weaker target of opportunity as a single Kindraa so that might not be a viable idea for some of the weaker ones.
Personally I've always liked Faraday-Tanaga. The Faraday bloodline seems to create excellent far-seeing and forward-thinking leaders. I also like their emphasis on scientific efforts.
On the outside looking in, it's easy to deride the Mandrills as a weak Clan and dismiss them. But from a roleplaying standpoint, playing a Mandrill character, or running a Kindraa, I've always viewed it as a really fun game or roleplaying opportunity.
Plus, they put SOO much emphasis on the bloodlines in this Clan. The bloodnames and bloodname houses are a big part of why I like the Clans. So it's hard for me not to like the Clan that put the most emphasis on the area I find the most fascinating. I loved that the Fire Mandrill section in FM: CC took the time to explain what bloodnames/bloodheritages each Kindraa had and how they used them, which bloodlines were superior at producing warriors of certain phenotypes, and which were the top dog names and so forth. That's the kind of detailed eugenics program/bloodname information I'd like to see on all the Clans.