Nothing that distracts your mind or eyes for more than a split second. If you want to talk, text or look at a screen then you need to stop your 2 ton vehicle. GPS voice instructions would be fine as it's the same as a passenger looking at a map and giving you directions.
That's a tough one. Distracting the driver would be the same as them talking on the phone. Ideally the driver would be separated from the passengers like a limo. Would you want your driver 100% focused on the road or would you want them to try and drive while trying to follow your conversation?