If someone is playing a PAL copy of a game is it possible to play against someone via local wireless who is using a US or Japanese copy of the same game?
I think that results may vary on how the game was published.
If the game used the same build for all regions (normally happens with games that have the same languages in every release), it surely will work.
If the game used different builds to some regions (like Puyo Puyo Tetris, the japanese version doesn't have western language options), it may vary if the devs actually thought in supporting a different titleID in their protocol, and if Switch OS actually let devs make the local multiplayer work in this way (opening channels between different games).
