The komik and manga of Naruto form the basis. The anime expands on it, adding movement and sound to enhance the experience. But there can be some differences in how scenes are presented.
The Sk8 the Infinity manga has indeed finished. It provided a satisfying conclusion to the characters' arcs and the overall storyline. However, fans still discuss and re-read it for the great moments.
Definitely. The anime Sk8 the Infinity originated from a manga. The anime adaptation tries to stay true to the key elements and storylines presented in the manga.