A: BeatAim uses same sensitivity as source games, so for ex. you can convert it to Apex Legends on https://www.mouse-sensitivity.com/

A: It could be a bug but remember that pausing the game for a long periods of time disqualifies your score, make sure you don't pause at all during whole song.

A: Yes, in game settings or change the config in BeatAim\BeatAim_Data\StreamingAssets\config.txt

A: For now game uses pure vertical degrees fov.
Easiest way to convert it:
1. Go to https://www.mouse-sensitivity.com/
2. Select your game
3. Select "Location" of your fov (In game, config, console etc)
4. Type your fov
5. At the top change to "Advance Mode"
6. Change FOV Type to Vdeg
7. Fov typed from 4. should be converted to vertical

Ex. 110 apex fov