Hi there!
You would be making great savings with the JR Pass.
Here's a quick breakdown of ticket prices without the JR Pass:
Tokyo - Aomori ¥ 17,480
Aomori - Sendai ¥ 11,310
Sendai - Tokyo ¥ 10,690
Tokyo - Takayama ¥ 14,000
Takayama - Kanazawa ¥ 5,440
Kanazawa - Osaka ¥ 7,240
For a total of ¥ 66,160 or ¥ 21,060 in savings as the 14 day JR Pass is ¥ 45,100. In addition you can also use the JR Pass for local travel around Tokyo and from the Airport.
I would recommend buying normal tickets for day 14-16. Local travel between Osaka - Kyoto and Nara is not very expansive. For instance a one way ticket Osaka - Kyoto is 540yen.
Something else I noticed is that you travel from Takayama - Shiragawa-go and return to Takayama before going on to Kanazawa. What you could do to avoid a good amount of travel hours is take a bus from Shirakawago to Kanazawa directly, instead of taking the bus back to Takayama and make a 4hour train ride to Kanazawa from there.
Hope this helps!
Daniel