oku-aizu region

Hi, my upcoming trip is on 2-9 Dec 2017 with my family (3 - all adults) and plan to tour around oku-aizu region. I intend to make aizu-wakamatsu my base staying near the train station. I have special interest to experience the Tadami Line all the way to Koide and back same day, or would you recommend to stay 1 night somewhere along this route?
For the rest of trip, I intend to book local tours maybe with govoyagin for sightseeing, to experience hot springs and local japanese cultures.

Question:
1. Is it more economical to get a JR East pass or full JR Pass? or i should just buy direct train ticket?
2. I would like to see the snow monkeys but i think it is too far or i dont have enough time. What is your opinion?

Thanks.