Todd Howard confirms that Fallout 76 will have no offline mode.

"Solo play" will include other players in the world, you just would be playing the questline by yourself rather than as part of a group. No NPCs in the game aside from robots. Every character you see will be a real human. The quests will be like how they were in Fallout 4, but instead of running into a group of raiders or something, you'll run into other human players.

They do not want it to be grief-y and will try to dial it in. They want a little bit of drama there, without other players ruining your game. VATs will still be in the game, but it's going to be real-time and will let you target and pick parts to attack.

They're treating it as a game as a service, where they hope to add stuff into the game constantly and tweaking as they learn what the players love and hate about the game as they play it. They love mods and are committed to making mods possible in Fallout 76, but it will not be available or possible at launch. But they hope to reach a point down the road where you can have your own private world and play with mods and they are committed to bringing that down the road

There WILL be private servers, maybe not at launch necessarily, that wasn't clear, but there will be private servers at least at some point. So you may still be able to do a solo Fallout 76 without having to deal with other people, however, the world will be extremely empty as there will be no other NPCs other than some robots.

Todd confirms that there is no remaster of Fallout 3, at least not right now, mentioning that you can experience it in 4K on Xbox One if you still want to play it right now.