Oh, something for the young? How about wrestling or something that wouldn't hurt anyone.
Oh, no ground games just mixes of strikes and throws? Sanda!
Oh, no kicks, knees, and elbows.... just boxing and greco.... Nope. that would be a horrible way to begin MMA. It's just limited for no good reasons. It doesn't add to safety in anyway and it limits the mindset of the fighter.
edit: On a second thought... This might be an okay combination if you had to teach a group quickly due to rather easy to learn and hard to master nature of the arts involved. For example if I had to quickly train a group of civilians how to hand to hand fight I might use this option. However for serious training into MMA it's a no-go.
The best base is what you are most skilled in. Even if you are not particularly skilled in one specific MA style, your advanced skills in what you are naturally good at could very well provide what you need to defend against any other style
I think you're trolling.
You know what would be the best base for mma? Like what you should start doing when you are young? Some sport where there is no ground game just mix of punching and takedowns, so no kicks and knees and elbows. Just takedowns of all kinds and boxing. First, no leg grabs, so greco and boxing and later freestyle and boxing what do you think? I should get a nobel prize
