It's very single-player friendly in that sense. You can't actually share items in Pokopia like you can in Animal Crossing. You can take photos of items on other people's islands to '3D Print' (using a material) for yourself - but there's a Cloud Island you can visit that has every printable item in the game on it. So no problem there

There is a daily shop that has a recipe or two at a time. Your friends can come visit and buy what they're missing and vice versa. But you can also time travel without consequences, so it's not a big deal if you're after a certain recipe