Well, perhaps if by "mine for a while", you mean "51% the coin while excluding anyone's transactions from the mined blocks", then that would be pretty close to what happened (if I remember correctly).
Totally not.
With a 51% attack
you can at most make half the blocks empty, not "exclude anyone's toes from mined blocks".
Nonsense. If you simply ignore everyone else's blocks, you can make *every* block empty as long as you have at least slightly more hashrate than everyone else, by mining your own blockchain in isolation from the network and leaking it out to the other nodes. If you have at least slightly more hashrate than everyone else, eventually your blockchain (with every block empty) will win.
Mining on top of other blocks found by other miners would pretty much defeat the purpose of a 51% attack. That would certainly be "amateur night at the 51% party." A correctly executed 51% attack mines on top of the attacker's own blocks, so they can override everyone else's blocks when their alternative blockchain with a higher chain trust is introduced to the network.