Greedfall 2: The Dying World will not follow the story of the original main character; instead, players will take control of a new main character. Greedfall 2: The Dying World is unlikely to reveal any new information about the characters and friends from the original Greedfall.
Will characters from Greedfall appear in Greedfall 2: The Dying World?
Greedfall 2: The Dying World is a prequel that takes place the old continent, which is mentioned in Greedfall. If you were hoping to see your old main character or old companions, Greedfall 2: The Dying World takes place before many of them have made the journey. Thus, the majority of the characters you see in Greedfall won't appear in Greedfall 2: The Dying World.
Some characters and companions from the original Greedfall may be present if they were native to Teer Fradee or Gacane three years before Greedfall took place. Seeing the main character may not happen, but at least there is a chance for familiarity with the characters who return.
The main character is from Teer Fradee and their companions may have travelled to other locations, so there is a small chance players hear more about companions from the first game that way—but that's not likely.
For more from Spiders, the developer of Greedfall, check out When does Steelrising release? here on Pro Game Guides!