Ok, let's get into the clan thing as well, while we're here.
The eight great clans are
- Kiranka
- Ki'ra
- Caxki
- Qarg
- Ragitagha
- Sutaghi
- Kurutak (also spelled Kur'u'tak)
- Sihkag
I also think that all Kilra'hra (commoners) belong to a clan, most certainly their local clan. That's because nobility makes no sense if there are no commoners assigned to the nobles. It's also safe to assume that most soldiers - I would even say most pilots - are commoners.
I think that you would notice it in their names (no 'nar' or something), but since it could also be possible that the 'nar' works like the German word 'von' in earlier times (and still in some southern German dialects). In those cases the word can either mean membership in a noble family, like in 'Otto von Bismarck', which is exactly like 'Thrakhath nar Kiranka', or it can mean from a certain place, like a village. I think it is the same with the Japanese particle-thingie 'no'. My Japanese is really bad but IIRC it is common if you call from Germany to say "Doitsu no Hans desu" meaning something like "This is Hans calling from Germany" (Doitsu is Germany, the 'no' means from in that context).
Whatever. What I'm trying to say is that it is possibly that even commoners might have a 'nar' in their names. I prefer the other version though, since it is also sort of supported by the books. We don't have many commoners in the books, actually I recall only one with a name at the moment, Jahkai. He doesn't have a 'nar'. EDIT: I forgot Dawx Jhorrad. He also lacks the 'nar' and is a confirmed commoner.
So commoners might not have their clans in their names, but for me it is certain that there is one clan (maybe more clans if you support the sub-clan theory) they owe fealty to.
Back to the clans: LOAF once made a list of words that come after 'nar' once in a book or game, and which might either be names of clans, or names of places, or both. I can't find it at the moment, but it is here in the forums archives, I'm sure.
EDIT: Now I found it, in this thread:
https://www.wcnews.com/chatzone/threads/kilrathi-clans.4039/
As for the maturity thing:
Interesting ideas here! Maybe Kilrathi are mature (in a biological sense) by the age of 4, so you can give them a laser rifle and use them as marines or so, but in order to have them fly fighters or for other complex tasks you have to give them further education, say, at least a few months more.
If they are nobles they might command ships at the age of 6 or so (like a 12-year old lord on a British ship during earlier centuries), but pilots may be a bit older. Ok, modern space fighters might not be as hard to fly as an F-16 jet, rather like a WW2 plane. And we know that could be learned in a dew months. (not great pilots, yeah, but those were sent to war back in the days).
As for having children: While the "pater familias" is still fertile they might not be allowed to reproduce, even though they might be able to, or the definition of being mature is different from the biological one, just like it is in most countries on Earth. Humans are able to reproduce at age 13-14 somewhere, but normally aren't encouraged or allowed to until they are 18-21.