marcie-complete the letters at aerodome island and buy her at pigpen's shop at campain for 1000 paw coins
sally-complete the letters at woods of monstec and buy her at pigpens shop for 1000 paw coins
rerun-complete the letters at front lines of verdun and buy for 1000 paw coins
pigpen-complete the letters at mines of matterhorn and buy him for 1000 paw coins
woodstock-complete his letters at verdon gorge and buy him for 1500 paw coins
baron-complete his letters at flying fortress and buy him for 1500 paw coins