I really hope they don't require the multiplayer section, and I really really hope that the "pokemon in the wild" isn't only available in the multiplayer area.
I don't play the Pokémon RPG for multiplayer aspects, and don't want them. I hated the brief forced interaction with the multiplayer region in Sun and Moon (or was it only USUM?), and definitely don't want my kids playing with anyone else.
That said, it's Nintendo, so I assume only people on your Friends list will appear there - so that's fine, we have a total of one person on our friends list so that'll be simpler.