What the hell difference does it make? As long as the Republicans hold up Lynch we have Holder. There is a line of Holder/Lynch candidates out there. You either pick one or continue with Holder. I don’t think he really wants to leave. I think he doesn’t want to answer committee questions. He can continue to avoid this as long as his resignation is on the table.
In terms of what either of them would do as AG, it doesn't make a difference. What these RINOs do not get is Holder leaving office and Lynch being nominated is a opportunity. Republicans could put the pressure on Lynch to the point that she gives up. Concurrently, they should be attacking Holder. This can continue with each nominee thrown at the Senate, since I am sure Obama will nominated only like minded people. The goal is to expose Democrats for what they really are while promoting conservative principles. Any opportunity for an argument is good. It will reflect poorly on Obama and more generally all Democrats.
The problem with Republicans is that they are impotent and too few actually have any principles.