Do you think I will be able to buy the second pre-order pack on ebay?

Maybe, but I personally don't think it would be worth extra money, but if you do go for it, people have been selling these things lately

Your choice. I wouldn't spend extra money on extra pre-order content. you will get over price and could lead to being ripped off. I know this guy from other website who brought over 4 different copies just to get the exclusive items. Again, "I Digress"!