Solid response. Nothing necessarily wrong with what you said. But I'll expand. Do you recall the Shakujo that Madara and Obito wielded when they initially became the Ten Tail's Jinchuuriki? If you look carefully, one represents the Sun and the other the Moon. It is carefully chosen imagery to represent Yin-Yang. In Daoism the concept of 'Wuji' represents Nothingness. It is the primordial state of the universe. From nothingness comes "everything," which we refer to as Taiji, the Supreme Ultimate. In Taiji, 'everything' is a state where there is no differentiation. Everything is the same, but there is a 'thing.' Now, after Madara obtains his other Rinnegan from Obito his Shakujo, which originally symbolized Yin, actually just becomes a staff with no difference on either end. It is this staff that represents Taiji. So do you see how the story is told in reverse?
In Daoism, Wuji comes first. And from Wuji, or nothingness, everything emerges - or Taiji, the Supreme Ultimate. Taiji is then separated into Yin and Yang. And from Yin and Yang you have the Bagua - or the 8 Trigrams, which leads to the Creation of All Things. This is how Naruto is told. The villains in the story attempt to reach this 'ultimate power' of Kaguya, which represents nothingness. Kaguya is Wuji, Madara is Taiji (initially he represents Yin, but becomes more as he gains the Yang half of the Kyuubi and his Rinnegan). Nothing represents this better than what Kaguya's ultimate plan is - to turn everyone into a mindless Zetsu clone which has no individual personality. Everyone is the same, which means there is 'nothing.'
Anyways, that's a really bad run down of the symbolism of Yin-Yang in the story. It is very prominent.
So yes, Yin-Yang when used simultaneously gives form to life, and life to form. Can one exist without the other in the RP? Can we have techniques that are 'purely' Yin or Yang?