does carplay work with bluetooth?

No, you will have to use a wired connection unless you have a 7th generation BMW 5 series outfitted with the newest head unit they have available for it, or install an Alpine iLX-107 receiver in your car (assuming you can actually find one for sale someplace...).

Depends on the model of car stereo system, some do support bluetooth car play but the majority of them need the phone to be plugged in