Answer from cs61c-el (David Tung 16479725) for Question 1
The EPC register holds the address of the address that causes an exception, while the cause register records why the exception was caused.  They are part of the coprocessor 0 registes.  To move them into registers, the command is mfco (dest) $13 for the cause register, and mfco (dest) $14 for the EPC register.