1) Nope, thats already real cheap
2) I think this really is something you'll have to answer for yourself. Personally I think that these holiday Z fares are a great deal, but I also can't imagine a transpac in Y. The fact that so many people make it is really a testament to the adaptability of man. Also while Z fares aren't upgradeable using certs you can do an UFC (upgrade for cash, at the gate) on Z fares to F.
3) Possible, but I would think not likely.