Answer from cs61c-ax (Amanda Alfonso 15906918) for Question 1
You need to pipeline the control as well because the control lines are inherently related to the datapath.  In fact, pipelining the datapath does NOT change the meaning of the control lines; it merely groups them by pipeline stage.  Without pipelining the control lines, then, it would be possible to have misalligned control lines - that is, each stage in the pipeline may or may not get the control signals it needs and instead they may all be concentrated at the ID/EX stage.