Well, first off -- David Boston is going to miss the season due to a knee injury from last Friday. Therefore, he won't have much of a comeback season.
Conway is supposedly buried on the Niners' depth chart. Expect them to go young and toy around with different scenarios. Overall, they know they're not in contention for a Super Bowl berth, so they'll give their young receivers as much playing time to gain experience for next season.
Driver could bounce back, but I still think that Javon Walker has the skills, potential and speed to be an elite WR. I think he'll continue to emerge as Favre's go-to receiver and Driver will have to battle Ferguson for the rest of Favre's offerings.
This leaves Booker as my main option out of your list to have a bounceback year. Thomas Jones should be a decent option on the ground, and will take some pressure off Grossman and the Bears passing game. As Grossman matures under center, Booker will reap the benefits. I think he'll increase in value as the season progresses.