You should also see this post:
https://support.khanacademy.org/hc/en-us/community/posts/7861911955085-Web-Audio-API-guidelines

I have questions regarding the guidelines for JavaScript/web pages that I would like to know before I continue working on my next programming project. Specifically, using disallowed functionality.

The guidelines (as of writing this post) say as follows:
- Don't store large amounts of data in localStorage or intentionally use the same keys as other programs
- Webpages should only create sounds using the files available to ProcessingJS programs or the Web Audio API oscillator.
- Webpages should also only play sounds in response to user interaction.
- Webpages should not play sounds immediately upon load.

I bolded the specific parts of the guidelines that interest me.

Issue 1: (The link at the top is a post about basically the same thing)
Webpages should only create sounds using the files available to ProcessingJS programs or the Web Audio API oscillator.
Technically, using an AudioBufferSourceNode filled with random values to create white noise is against the guidelines. However, as most people probably feel, it is not against the overall 'spirit' of the guidelines. I don't see any programs using this getting hidden for using this, but it would be nice to see an answer from a guardian regarding this.

Issue 2:
Webpages should only play sounds in response to user interaction
I believe this is added to the guidelines for accessibility purposes. However, there are some things that technically wouldn't break the guidelines. For example, starting a music track when the player presses any button on their keyboard. Once again, I feel that playing background music for a game is not against the spirit of the guidelines, but I'm still unsure.
Edit: I'm really just asking if playing background music for games is against the guidelines

Issue 3:
This part isn't really an issue, or rather "would my program be hidden if this is what it did."
I know there was an old program that would let users compose and add music to their projects, but it did not follow the guidelines. I wanted to make something similar, without breaking any guidelines. As stated in a comment on the post from the beginning, guardians don't have the time to look through every single line of code to check if a program breaks the guidelines. They probably just run the program and determine if it looks like it breaks them.
That being said, would these features of my program make my program get hidden?
 - Import midi files with a file input
 - Save midi files
 - Save audio files
 - Use white noise AudioBufferSourceNodes for instruments
And the one that follows the guidelines the least:
 - Add an option to export code for PJS (not webpage) programs that will make oscillators to play sounds

I appreciate any input you people on KA have. I'm currently eating lunch at school as of writing this, so I don't have time to re-read what I have written. If you want clarification on anything, just ask and I will do my best.

TLDR:
- Is using AudioBufferSourceNodes to play white noise against the guidelines
- Is playing background music in games against the guidelines
- Honestly just read issue 3, I don't feel like re-explaining it here