Osaka-Hakuba-Tokyo

My partner and I are currently planning our first trip to Japan and would really appreciate some advice/suggestions about our trip. We have been reading up on the various transport options but this has confused us more! We are wondering if it is worth getting a JR Pass or individual tickets for our proposed itinerary below.

Osaka 19/12-26/12 We fly into Osaka have a private transfer to Hotel Kinki
During our time in Osaka we will be catching up with friends, doing a day trip to Hiroshima, seeing the sights of Osaka (aquarium, Universal Studios, Umeda Sky, Shitennoji Temple & Osaka Castle) and a day trip to Kyoto.

27/12-28/12 We are also keen to go skiing & have been told that Hakuba would be good place to go, we only want to spend 1 or 2 nights here and then go onto Tokyo. What is the best way to get from Osaka to Hakuba and then Tokyo?

Tokyo 29/12-4/1 Fly out of Tokyo.
We are staying at Sakura Ikebukuro and will be out and about seeing the sights of Toyko (Disneyland, Tsukiji Fish market, Akihabara, Shibuya, Harajuku, Ueno park, Sensoji temple, Rikugien). Then either go by train or private transfer to the airport.

Any advice or suggestions would be greatly appreciated!

There are direct overnight buses between Osaka and Hakuba and between Hakuba and Tokyo, but for more comfort, I recommend to travel by train. The basics are explained under "How to get there" towards the bottom of the following page:
http://www.japan-guide.com/e/e6090.html

During your days in Tokyo, I suggest that you plan things well because your stay overlaps with the New Year holidays - Tsukiji market is likely close on the 31st, then 1 - 3rd or so (please check their calendar later in the year); Sensoji temple will be awfully packed startiing on Jan. 1st; Disneyland is likely very packed on the New Year's Eve maybe with some party - recommended to book if that's the event you are after :). Other shopping areas will be closed only on the 1st but will be open from the 2nd :)