Answer from cs61c-eo (James McBryan 16730959) for Question 1
No each instruction has a unique distinction.  Many parts of each MIPS code may be the same but the entire 32 bits including some that are placed in the PC are never the same unless the code is exactly the same.  If the instructions were the same then the processor could not differentiate the code from another.  The whole purpose of the assembly language is to reduce a nonenumerable set of complex code to a reduced, simple basis that all of it can be represented with.