One common theme could be the clash of different cultures and power systems. Naruto's ninja world and the Star Wars universe have very different ways of using power. Another theme might be the relationship between Sith Naruto and Padme. How their different personalities and moral compasses interact, whether it's a love - hate relationship or a partnership of some sort.
The novel of Revenge of the Sith is canon. It aligns with the established Star Wars canon framework and adds depth and detail to the events depicted in the movie of the same name.
There are several places to look for 'Sith Naruto x Padme' fanfiction. Fanfiction.net and Archive of Our Own (AO3) are great platforms. On AO3, you can use the search bar and type in 'Sith Naruto x Padme' to find relevant stories. However, the availability might vary as it depends on what authors have created and shared.
Anakin Skywalker and Obi - Wan Kenobi are main characters. Anakin's fall to the dark side is a major part of the story, and Obi - Wan is his former mentor.