Answer from cs61c-ev (Roland Carlos 16583196) for Question 1
No, but it can come close. Since different formats have sections that use the same space in the 32 bit area (for example, rd, shamt, and funct in r-format all equal address in i-format) and it's possible that part of the bit pattern for something in one format could equal something in another format (but mean something completely different), the op field is always constant in each format, and tells the machine actually what operation to carry out. While the op field helps the machine differentiate between operations, sometimes the op field is the same for two different ops, in which case the funct field is also used. So no bit pattern can be the same and represent two instructions.