Answer 2: Ivy Bridge has the same number of PCIe lanes as Sandy Bridge.
Answer: It depends on the board. If the manufacturer has overused the PCIe lanes such that switching is necessary, then no, not even with IB could you use all of them at once.
EDIT: Adding more PCIe lanes would need more traces to the CPU and require a new CPU socket.
Perfect, thanks. That's just what I needed to know.