Japan Rail Pass (before the price rise, 14-day)
is too expensive for your itinerary.
JR-West Kansai-Hiroshima Area Pass (5-day),
on the condition
that you visit Hiroshima and Himeji within 5 calendar days,
sounds good for you to go outside Kyoto City | Osaka City and back.
https://www.japan-guide.com/e/e2361_kansai_hiroshima.htmlEven when you, for a special reason,
cannot visit Himeji on one of the 5 days,
Japan Rail Pass (7-day) does not sound best.
----
JR Kansai Area Pass (which includes Kyoto Subway One Day Card, Keihan 1-Day Kyoto Sightseeing Pass, Hankyu 1-Day Kyoto Line Free Pass) These are separate passes; no one includes any other.
JR Kansai Thru Pass Kansai Thru Pass is a non-JR pass.
(Your source may be unreliable.)
----
When you travel
with JR-West Kansai-Hiroshima Area Pass,
for the section Hiroshima -- Okayama -- Himeji -- Shin-Ōsaka,
you can take faster Nozomi and Mizuho trains,
which JRP travelers cannot take.
On the other hand,
between Shin-Ōsaka and Kyōto,
you go by the conventional [non-Shinkansen] line.
It's because the Tōkaidō Shinkansen
(Shin-Ōsaka -- Kyōto -- Nagoya -- Tōkyō)
is operated by JR-Central.
Special Rapid trains are available frequently
for the section
Himeji -- Sannomiya (in Kobe) -- Ōsaka -- Shin-Ōsaka -- Kyōto.
You stay in the Umeda area, i.e. near Ōsaka Station,
so you need to take a non-Shinkansen train,
regardless of which tickets you travel with.
----
Day 3: Day trip to Hiroshima Will you visit Miyajima Island?
What date is your Day 1?
