Keep Olofsson. The young guys coming in next season are going to have their ups and downs. Having Olofsson as a scorer can help their transition, and take some pressure off them.
If the young guys mature quickly, Olofsson's contract will still be tradeable next year or the year after.
At this point, if Anderson wants to play another season, I'd keep him too. The team rallies around him and he enjoys playing with the young guys.
These two guys are more important to the team's development arc right now than mid round draft picks.