The Wireless adapter, while it was initially introduced, released, and bundled with Pokemon FRLG, is not exclusive for those games alone. You could say that the accessory was best promoted with FRLG because Pokemon is a popular franchise.
Pokewalker may be technically considered a remake of the pedometer/virtual pet toy, Pokemon Pikachu GS, which was released back in Gen 2, and can communicate with GSC through Mystery Gift. With the Global Link offering countless possibilities and methods of obtaining Poikemon, and 3DS having a pedometer function, I don't think we'll get another similar gimmick.
Back in Gen 3, the Japanese got the e-Reader. It's a GBA peripheral that lets you scan special cards that let's you unlock stuff in games. Various e-cards were released, one of which is the Eon Ticket for RS. The closest thing we have for the 3DS are the AR Cards. So, you can go ahead and speculate if physical copies of the game would come bundled with an AR Card that could unlock tickets to the event islands.
That could also work.
But considering that they plan on releasing it next year, obviously it can't be bundled with ORAS.