Yes, if you are using an older generation of Bluetooth on one item, the second device can still pair and function.
AUKEY AiPower enabled USB ports provide the safest maximum charging speed for all your different devices for a healthier battery function. The green color identifies the AiPower ports on your AUKEY products.
Yes, they can stay plugged in when not in use. However even if the car is not running, the charger will continue to use a small amount of battery power, even if there is no device plugged in. This could affect the battery of your car if it is not driven for long periods of time.