JR pass worth it?

Travelling for 8 days in Japan in July.
2 adults/ 3 children (11,9 and 2 years old).

Fly into Osaka and stay 4 nights hotel in Osaka (which we will use as base). Hope to see Kyoto, Osaka, Nara and possibly Hiroshima.

Then, take bullet train one way to Tokyo and stay in Tokyo 4 nights (shop, sight see around Tokyo and vicinity, Disneyland). Then take train to Narita airport for departure.

So is it worth it to buy the 7 day JR pass knowing the biggest cost if I paid for tickets separately would be the one way (not round trip) from Osaka to Tokyo and to a lesser extent the ticket to the Narita airport from Tokyo?

Or

Buy the JR Kansai west pass for 4 days during my time in Osaka and area and pay separately for the bulltet train one way to Tokyo. And then buy a local pass for Tokyo.

I know there is some value for convenience travelling with 3 kids. So, would it make sense to just buy the 7 day JR? or not?