Hi JesBostonMA. We have a similar plan...we are going to Bariloche with our kids..though we are only planning 4 months (starting in June). We should put our heads together re: childcare, schools, housing, getting money at a reasonable rate, local rates for flights within ARG, local ski pass rates, etc. We have done some research, but little on cars so we appreciated reading your post. We plan to rent a car at first.
Resident ski pases for the 2015 season (AR$1800) were only sold until January 2015 and you needed to have been living for 6 months in Bariloche prior to purchasing them; then of course prove that you were a resident in Bariloche, DNI with Bariloche address etc.. It's an expensive place to ski. A adult daily ski pass, high season last year was over AR$600...this year I'm sure it will be over AR$700, the season pass was AR$18,300 last year.
For local flights; if it's the same as it used to be (havent seen many comments about it recently) then purchase your ticket and check-in online and travel with no hold luggage so you can go straight to the gate and don't need you show your id at the check-in desk.
Money: Xoom appears to have a pick up point in San Martin, though it doesn't look very official: https://www.google.com.ar/maps/place/Eduardo+Elordi+614,+San+Mart%C3%ADn+de+Los+Andes,+Neuqu%C3%A9n/@-40.154336,-71.349336,3a,62.8y,48.82h,87.55t/data=!3m4!1e1!3m2!1stHvFgyjpvero9mueoIOwKQ!2e0!4m2!3m1!1s0x96110e771a5fa6a3:0xd280994f8df80baf!6m1!1e1?hl=en
They also state on their website that they have various pick up points in Osorno, Puerto Varas & Puerto Montt -.
Azimo's nearest pick up point ot Bariloche is in Puerto Madryn. I don't think is currently has any pickups in the Osorno region.
Or withdraw at the ATM's in Osorno then change to us$ in the casa de cambios or banks in Osorno.
Rental cars are currently about $3000 - $4000 per week, although I'm sure you would get a discount for a 4 month rental.
For 4 months in the high season you should start looking for a place to stay now, most places will already have some reservations over the winter season. Either reserve before you arrive (paying up from in us$) or wait until you arrive (much less options) and maybe find something in AR$.