Answer from cs61c-an (Ben Weil 16819970) for Question 3
THe hazard unit controls the PC and instruction fetch so when it detects the necessary conditions for a bubble, deasserting the control signals and essentially have each previous stage of the pipeline repeat what it did in the previous stage so that the lw may progress.  The condition for the hazard would no longer be true since the lw would have advanced one stage.