MCR looks like a good target but the management is too good, so I can't see ZFX will be running those mines any better. I would say ZFX would forget about nickel and go for copper. CUO and PNA look good as long term prospects are good. They would also be earnings positive. With 2b, ZFX would have no problem borrowing an extra billion to help fun these purchases.
There is also the up coming RIO sale of assets.