1. Taxis can be booked by phone through the TransAD hotline 600 535353 or via the Abu Dhabi Taxi app available for both iOS and Android platforms.
2. No. Taxi drivers do not need to be included in your entry/exit permit.
3. You can ask that aspect while booking. For orientation the fares are listed here https://visitabudhabi.ae/en/travel/around.the.emirate/taxis.aspx