JR Pass + Kansai Thru Pass? 11 day Itinerary

Hello, I will be spending 11 days in Japan from Dec 25 - Jan 3. Here is is my planned itinerary:

Dec 25: Arrival to Tokyo, take shinkansen to Osaka
Dec 26-27: osaka to Kyoto and return
Dec 28: Osaka - Nara - Kobe - Osaka
dec 29 : Osaka - Miyajima/Hiroshima - Osaka
Dec 30: Osaka - Takayama (via Nagoya) will stay overnight
Dec 31 - Takayama - Shirakawago - Tokyo
Jan 1-3: Tokyo

Osaka will be my based area, so I'll be going back to Osaka every night. I have done my calculations via Hyperdia and JR calculator and it says that I will get my moneys worth.

I have no specific Itinerary per cities yet but I will definitely visit temples, castle, those touristy places and will do some food tripping. My main questions are the following:

1. Can I use my 7 day JR Rail pass as a JR West Kansai Rail pass? I'm getting confused as other blogs states that I should get 3-4 day JR West Kansai Rail pass

2. Do i also need to get the Kansai Thru Pass based on my itinerary? or my JR Pass is enough?

3. Since I will be activating my JR pass on the first day and it will expire once I get to Tokyo, how will I go around? Is there another pass or subway card that I should purchase to go around?

4. My itinerary is not yet final, I am still trying to figure out if arriving in Osaka and departing to Tokyo is a better schedule, if so will be JR pass still be worth it?

5. Oh and I hope someone can give me some insight but if given a choice, where would you like to spend your new year? In Osaka or Tokyo?
   I just read that the Kansai region is almost full of people during the new year because locals would go home, the truth is i would like to avoid that crowd but at the same time, Tokyo is much expensive on the new year.

I know I posted a lot of question but any kind of help and replies will be very much appreciated.

Thanks!!