I'll leave the Audi and the Crown Victorias (all the taxis are Crown Vics, there's no Caprices) to their respective experts.

Unknown background car: Infiniti G35 ('3-'6).
Dodge Caravan?: Toyota Sienna ('4-'5)
Unknown background car (blue minivan): Dodge Caravan or Chrysler Town & Country ('0-'7).
Unknown background car (white sedan): Acura Legend ('91-'95)
Unknown Ford: Expedition ('97-'98)
Honda Civic?: Accord ('94-'97)
Chrysler?: Town & Country ('98-'0)
Unknown (blue van): Chevrolet Express/GMC Savana