these are my theories i hope you'll like it and please don't consider it as cannon However there still a working progress
Metal release (金遁, Kinton) is an advanced element composed of tow elements Earth and yin release.
The metal will be created by the yin release starting from Earth itself, since the yin element can create form out of nothingess.Sun release
Sun release (日遁, Nitton) is an advanced element produced by the mix of lightning, fire, and yin release
the sun is a body made of plasma, the resulte of mixing fire and lightning elements , adding the form creating aspect of yin release the plasma will be held together by gravity and the sun will be created.Hurrican release
Hurrican release(颶遁, Guton) is an advanced element composed of wind, lightning and water .
A Hurricane is a natural phenemenon usually followed by other metrological events such as thunderstorms, strong winds and heavy rain wich all have a relation with the elements that the hurrican release is composed of.Acid release
Acid release (酸遁, Santon) is an advanced element composed of water ,fire and yang release.
by mixing fire and water boil release will be produced, and the yang element will icrease its acidity to form a corrosive substance , Acid.
Flora release (植遁, Shokuton) is an advanced element composed of earth, water and yang release.
mixing earth and water release will produce the wood release , and the yang element will empower its life force producing an entire flora of variouse plant lifes.
Ocean Release (洋遁, Yōton) is the resulte of mixing water, yin and yang release
the yang release's life and physical energy will empower the water release to a much higher degree, and the yin release's form creating power will increase the concentration of salt in the water and give it a higher conductivity due to its high ion concentration all these are the characteristics that we find in an ocean .