Where am I able to buy train pass tickets (Navigo week OR Paris Visite) at CDG airport terminal 1?
Can I buy the Navigo weekly pass at the airport if I don't live in Paris?
You can buy a Navigo Week Pass or a Paris Visite at the train tickets window inside the CDG T1/T3 train station (known as "Roissypole" on CDG airport maps and the CDGVAL shuttle train). See the linked article for a photo of the ticket window inside Roissypole.
Residents and tourists/visitors can both purchase the Navigo Découverte card (to use with a week pass). This version of the card doesn't have your name & photo printed onto the plastic card itself, rather it comes with a paper card you write your name & paste your photo onto. Then you carry this personalized paper card along with the non-personalized plastic smart card of the Navigo Découverte for it to be "valid".