So, I recently saw a discussion here regarding misako's element, and in the discussion, many people theorized that Misako has an element due to the fact that she can do Spinjitzu, a grey-silver colored Spinjitzu. I couldn't reply to that discussion as it was archived, so I decided to make a new one.
When the first Spinjitzu master created the MARTIAL ART of Spinjitzu, I very much doubt he limited the art to only elemental masters.
Misako very well does NOT have an element, as she, along with 2 others (Aspheera and doubloon) can perform Spinjitzu, and all the primary and secondary elements/essences have already been revealed.
As for the color. Spinjitzu is an art that can be tought. As shown in the fire chapter, Wu was able to teach Aspheera Spinjitzu. Some say that Aspheera possesses the element of magic, but magic, nor dark magic, is NOT an element, it's simply a force that can be used by anyone with sufficient training (Clouse is a good example). Aspheera's Spinjitzu is a fiery red, which looks very similar in appearance to kai's Spinjitzu. This is because Aspheera is a pyro viper, and they presumably have the ability to harness the power of fire, as shown when she absorbed kai's fire.
Doubloon can also do spinjitzu, so it basically throws the "You can only do spinjitzu if you have an element" theory out of the window.
As for their colors, In season 1, Zane at one point had his gi dyed pink, and during his fight with the serpentine, his spinjitzu was also pink. This means that the color of spinjitzu mostly matters on the color of your clothes/hair/skin. This is also evidenced by Misako having grey spinjitzu as her hair is grey, and doubloon having orange spinjitzu because of his orange skin/armor.
Thus, I conclude that you do not need an element to do spinjitzu, and the color of your spinjitzu matters on the colors of your body or your clothes
This is my explanation, feel free to ask questions.