For the first problem, I propose using a global variable like a boolean to know if you need to restart the music or not.
For example:
- Set a boolean variable start_music.
- In all the main menu buttons set the boolean to False before the action Go to the main menu layout.
- Then in the Main Menu event sheet add a new condition Is boolean set to the At the start of the layout condition that you already have, so when both conditions are meet the music will restart otherwise it will keep going.
It is just an idea of how you can fix your problem.
On another separate issue, I suggest that you open different topics for each problem that you have, I think that way people can glimpse at your title and go like "Oh I can help to solve that problem".