You can book a cab via following methods:
Online: http://www.airporttaxiseattle.net
Telephone: +12062190957
Email: limo@airporttaxiseattle.net
Yes, it's possible to pre-book a cab with Seattle Airport Taxi, please contact the company.
Seattle Airport Taxi has both regular and air-conditioned cabs, please mention your preference at the time of booking.
Please contact the company on their helpline number to make any changes.
Generally drivers will meet the passengers at the arrivals on airport pick ups but do check with the company.