Travel together

Hi a friend and I are visiting next month. We are travelling from Tokyo down to Kyoto. From Tokyo we go to Matsumoto ( 7/10/24), Nagamo (10/10/24), Kanazawa (10/10/24) Takayama (11/10/24), Hiroshima, leaving on 18/10/24. We are thinking to buy a rail pass from Matsumoto to cover the last few days. We were thinking to get a seven day pass from Takayama or Kanazawa but were unsure where we can collect the pass - can you only collect it in certain stations?

Also if we buy our rail passes separately, can we then book seats sitting together? Thanks. Karen