There are some minor differences, and you would have to get the phone to accept the Sprint PRL over the Verizon one, which may be another issue in and of itself.
But since B and C are so much more likely to bar porting a phone than A is, we will probably never know for certain.
Though if the rumor mills are true, Sprint doesn't have long to wait before they get an iPhone of their own.
Oh, and I forgot a point D) You risk getting your account closed and banned from ever becoming a (primary) Sprint customer again
I worked for Sprint for a number of years, I wouldn't put it past them.
In any case, though, unlocking only makes sense and only works for GSM phones.