Which Pass To Buy

Hi,

My family (2 adults and 2 kids- 5.10 & 2 years) are planning to visit Japan for the first time and need some assistance on the below: My itinerary would be spending:

Arrival : Kansai Airport (9.25pm)
8th to 14th Oct: Stay Awagi Island (Heian-Ura Aiga-Cho, Hyogo-Ken)
15th Oct : Travel to (Kitakaruizawa ,Naganohara-Machi, Gunma-Ken)
15th to 19th : 4 night stay (Kitakaruizawa ,Naganohara-Machi, Gunma-Ken, 377-1412) and would be making a trip to Disneyland Tokyo in between.
Departure: Haneda Airport(11.45pm)

Given the above, I am not sure what JR Pass that I need to buy and if one of my kid also requires a pass to be bought?

Alternatively , given the 2 kids and my travel itinerary , would a car be more suitable.

Thanks, Kumar