Is local multiplayer (local network, multiple consoles) possible on Doom on Nintendo Switch?
Solution 1:
As of date, it's not possible to have multiplayer session just for local party.
However, it has party option which allows to play online multiplayer with your friends (as like you, your friends and bunch of other folks on the same server). You can see party option in bottom right corner:
As for accounts, on Nintendo game store's Doom page it is listed that:
Nintendo Account required. Online features will be free until the Nintendo Switch Online Service launches in 2018
So I think all players need copy of game and Online Service subscription.