The left speaker makes a weird, muffled rattling sound?

I recently purchased a second-hand vehicle listed above Touring with 118,000 km, and I've noticed a few issues after driving it for a while:

Left Speaker Issue: The left speaker makes a weird, muffled rattling sound when the bass hits in songs, regardless of the volume. A friend suggested it could be a loose wire causing the rattling when driving or from the bass vibrations.

Park Gear Problem: The car rolls slightly when put into park, regardless of the angle, and sometimes it doesn't detect it's in park. I read that this could be due to a worn-out rubber band in the system. My temporary solution has been holding the clutch while in park when turning off the keyless start, so it recognizes it's in park and doesn't go into accessory mode.

Brake Noise: Occasionally, the brakes make a faint whistling sound. They still work smoothly, but the noise is concerning.