Well, KitKat wise, couldn't find any beyond the odd chemist and Don Quixote.
Mostly the same 3 or 4 varieties. Not even touristy places Google mentions had any eg Ekie.
Tonnes of lemon orientated things at tourist prices at Hiroshima Station today.

Anyway, just booked my Hiroshima to Shin-Osaka Shinkansen last night. No discount and paid a little over 10000 Yen for the non-green car, about 4k cheaper than the green card.
Quite a few seats left when I booked, but it filled up a bit and I ended up with a seatmate at the first stop - Green car seats definitely more comfortable.
Train seemed to be going through tunnels for 90% of the journey. Different routes as I cant remember that many coming from Tokyo.

Anyway, got off at Shin-Osaka and went through the JR West gates (Google told me to). Spotted a sign that said Kansai Airport, where I wanted to be, and after a 20 min wait, a "Hello Kitty" train arrived (artwork outside and minimal inside)

Didn't know you needed a ticket on top of your IC card for that particular train.
Anyway, paid 1200 Yen to the conductor and 1400ish on my IC when leaving the airport

Thought the exit machine would have wanted my ticket, but my Suica card let me through (did have to find an ATM and top it up as I was 400 Yen short and 90% of the machines don't seem to accept cards, only cash). Handily one near the top of the stairs from the platform.

Fanta wise, have seen While Peach, Orange and grape varieties. None sugar free (just Pepsi and Coke)
Back in the UK, we would have 20+ soft drinks to choose from yet Japan seems to nearly all be tea or coffee.