Should the film editor have music knowledge to edit a film?

Editing is different with Sound editing .Although they share same process both crafts are slightly different but overall film editor need to take care of all other processes like sound editing,mixing etc ,so overall in depth of Sound editing is not required but he should have overall idea of the sound editing.But in real world scenarios all editors will have in depth knowledge on sound/music .Because film is combination of visual with Sound so a film editor ultimately learns the sound knowledge

I have written a story and I want to convert it into a screenplay for a movie. How do I do it?

While story writing is a more narrating experience while film scripts are more visual experience.You must have understand your character thoughts,actions ,behavior very thoroughly and have to use this in scripts instead of explaining everything o viewer .So dialogue writing is a great skill that must to be learned by every aspiring screen writer.Online so many templates are there for screenwriting and you can read those examples for technical ,at first its very confusing but you have to practice everyday a page so that you can learn script writing

What cinematography textbooks do you highly recommend?

Film directing shot by shot by steve katz

This book is part of many seminars in film schools as a graduation study.discusses on all various shots and when to use which type of shots,blocking film scenes etc

5 c of cinematography

This has everything that a cinematographer should know although the concepts are little bit outdated still a great read

Master class series

best books on all types of shots in cinematography