Although the bulk of the Animal Crossing: New Horizons Direct today mostly dealt with cute animal interactions and small nuances that hardcore fans will notice, there was an "FAQ" section at the end that touched on a few hard-hitting questions.
Nintendo cleared up the multiplayer aspect of the game, explaining just how families will share islands: "With one Switch system and a game, up to eight people can live on one island (which is the max). Each user can register one resident with its own house." To use tools like shovels and axes (which can ruin layouts and structures), you need to be flagged as a "best friend" (similar to a Real ID in Battle.net or another similar service).
The game will support amiibo figures and cards from the Animal Crossing series. Not a whole lot of detail was provided, but you can see all of the 100% confirmed figures and cards in the gallery below, which were shown off on the stream. Scanning an amiibo and having a character show up was teased, as was the Phototopia photo opp location (which is literally just photo shoots with cute animals).
Free seasonal updates are also coming, including "Bunny Day" (Easter), which is arriving on the March 20 launch. That's in addition to an app called "Nook Link," that's coming in "March 2020," likely a little ahead of launch.