Yes. You can add and have an obligation to add anyone who drives your vehicles. This does not mean that you can add their vehicles onto your policy. You cannot insure a vehicle that you do not own.
If he is a member of your household or if he drives your vehicle then yes he must be added to your insurance policy. A member of your household includes students away at college. A student at college does not count as not living with you because their residence is still your house.
Yes, as long as you add her as a regular driver on your insurance policy.
If your daughter does not live with you but drives your vehicles then she is still required to be listed as a driver on your policy. The policy states that all household members and regular drivers must be listed. A regular driver is anyone who drives your vehicles sometimes. This does not mean you can add a car titled to her on your policy even if she is listed as a driver but she is still required to be listed as a driver on your policy. If she is an adult driver it probably won't cost you anything anyway.
You add them when they get their drivers license, or anytime after that.
You will have to check with your insurance company. Many insurance companies will cover a driver when you have loaned them your car but have age restrictions.
I heard you do not have to add your 16 year old to your car insurance policy since he/she will only be driving your insured car. Is this true?
If the 16 year old grandchild lives in your home or drives your vehicles then yes you are required to add him or her you your insurance as a primary or secondary driver depending on how much they drive.
You can add your roommate to your auto policy as a driver but you cannot add their vehicle to your policy. You cannot insure a vehicle you do not own and since you have no legal relationship with a roommate you cannot add a vehicle they own to your policy. You do have an obligation to add them as a driver on your policy if they ever drive your car.
Only if he as a multiple driver policy. If not, then no, you would not be covered in the event of an accident. He could add you to his policy- just call the insurance company with the details. Not unless she is listed as atleast an occasional operator on his insurance policy.
As long as she has your permission, she can drive the vehicle and she will be covered. If she drives it more than a few times, you should add her to the policy.