Rail pass for Kyoto, Osaka & Tokyo

We have booked our travel in year end and planning an easy itinerary since we're travelling with 2 young children. We will arrive at Kansai Airport and departing from Tokyo Haneda. Our first leg starts from Kyoto.

My travel plan:
5 Nights Kyoto - Places of interests in Kyoto, Nara
3 Nights Osaka - Places of interests in Osaka , Himeiji
6 Nights Tokyo - Places of interests in Tokyo, Disneyland (maybe around Tokyo)

My idea of Rail Pass purchase:
1-Way Haruka + ICOCA (for Kansai area and Tokyo)
1-Way JR Hikari or Nazomi Shinkansen (from Osaka to Tokyo)

Questions:
1). Is ICOCA good for all subways in Kyoto too? or do I need to buy a separate Kyoto local card?
2). For travel to Nara/Osaka and Himeiji, should I make use of ICOCA or is it more economical to buy a Kansai Thru Pass?
3). And ICOCA for Tokyo, is it fine using this card or any other recommendation?
4). If I will to add a day trip to Hiroshima (from Kyoto), will it be more economical to buy the 7-Day JR Pass?
5). What is this Kansai One Pass? Does it has more coverage than ICOCA and perhaps be using it for my Kyoto and Osaka stay?

Appreciate your advice.

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