1: Yes, they regularly update the roadmap and post screenshots of upcoming content. We've got "The Cult of the Wolf" update coming in Q1 2022 and the long awaited Mistlands update in Q2 or Q3. I get most of my Valheim update info 3rd hand, but I'm sure someone will post a link to the official news site below.

2: No, there's no plans that I know of to add NPCs in the future (except for Haldor of course). But you can tame wolves and lox to keep you company and fight alongside you :)