Apple has not yet officially announced Apple Pay Octopus but the latest iOS 13 beta (developer beta 4/public beta 3) now mentions ‘travel cards’ and ‘public transport’ in the Wallet initial add card screen blurb when the iOS region is set to Hong Kong. You cannot add Octopus yet as that won’t happen until the official release.
No word yet on iPhone 7 and Apple Pay Octopus support, we won’t find out until Apple and OCL announce the officially supported device list, it should be coming soon. Meanwhile FeliCa Dude wrote a very informative Reddit post that definitively covers every facet of iPhone 7 FeliCa support, from Octopus to iOS 13 Core NFC. It’s amazing stuff.