JesusWalks,
I can see where your worries stem with children getting into more fights than adults. Personally, if I thought someone was going to misapply a combative that they wanted me to teach them the would be denied training and asked not to re-inquire. My feelings on the matter (and this answers a few of your other statements) are pretty simple: Proposed students have the mindset to properly apply what I teach or they don't; I don't care what gender they are, what color of skin they have, their sexual preference, or what personal worldview they hold.
You seem very tied to your culture and religious convictions. While I can understand where you are coming from, my thoughts are stated at the end of the previous paragraph.
In regards to stamina I can see why its harder with kids due to their developing bodies, but I don't see how its impossible. Stacked with the judo and ukemi work stamina training could give them 2-3 years of work on their plate and offer you a very viable student in the long run. If you were meaning that you couldn't feel right with pushing kids to their collapsing points, real students of combative arts should willingly be doing that to themselves.
Also, for what its worth, I applaud your requirements for well-roundedness.
In our state they have actually relaxed the laws quite a bit as far as leathal force, they have what is called a stand your ground law, if someone attacks you, you dont have to make an attempt to run or hid and risk loss of property you can kill them on the spot and are automaticly relased from any legal persecution.
In Florida, even though we have castle doctrine, stand your ground, and the whole defensive bit outside of open carry and switchblades, some DAs are still anti and will drag a victim to court even if it was a lawful shooting and they really lay into them if there happen to be some holes in the back or if there was a statement saying the aggressor was on the ground. Its a good idea not to feed politicians anything.
Usually when I go into situations where something like that is more likely to occue I have a buddy with me that sports a H&K subcompact and an M-4. I have a remake of the G-3 with a 3-9 power leopold scope, a real G-3 is about 3,500$ so maybe I will get one one of these days. With the firepower we carry there should be no need for a mag change since we are both military trained.
I'm guessing you have a CETME then if its a G-3 clone and not a HK91. I'm also guessing your friend has a carbine sized AR-15 and not an M-4 since you don't seem to know (from what you've written about the G3) about NFA item transfers and laws.
In a fight I'd classify as worthy of keeping a carbine or battle rifle on hand, I'd want spare mags; because to get that far that means I'm expecting a paramilitary force to present opposition or anticipating long distance work (up in Alaska, I can see keeping the G3 clone on hand for bears though). Luckily, I've never been presented with such situations in the real world. Also, don't rely on military training. Its not perfect by any means at least judging by the current active regular soldiers I've outperformed in classes, placed above in competitions, and neutralized in simmunitions force on force fights.
Not trying to dog you, but I seriously believe you should examine your defense routine and preparations.
I studied ninjisu in denver colorado under shidoshi speakman and he was a 6th or 7th degree, when I found the school and was training I had no idea how rare it was to find someone who taught it until I moved back to alaska now im disapointed because there are no schools up here that teach it but a least I can finish up getting my TKD black belt, the TKD I had before was more combat oriented, for thoes impractical kicks, he would demonstrate them and have us do a few and that was it, he focused on stuff we could actually use, and then in ninjitsu it was all practical.
Ninjitsu is a hard one to get a credible instructor for. Speakman has good creds since he has studied under Hatsumi. I bet you got some pretty good instruction at his dojo.
TKD, while not an awe inspiringly strong art, has its merits if its taught as a combative instead of as a sport. I don't know Speakman's curriculum and how it deviates from the Bujinkan's or how far you got in it, but its possible your TKD could be a linear supplement to your ninjitsu.