How many Bitcoins are from money laundering operations?
This question doesn't make sense. The literal answer is that all bitcoins are a result of mining. Perhaps you could rephrase it?
So if there were no transactions available with fees, would those miners just get no blocks at all?
No, they could still get blocks, they could simply refuse to place transactions in them.
This brings me to an interesting prisoner's dilemma with Bitcoin. You can mine empty blocks, effectively stopping the network. If the miners purposely damage the network they in turn can't spend their own bitcoins on anything. If a miner has enough power to damage the network, then it stands to reason they have enough power to continue supporting it. Chances are, they gain more from supporting it than they do trying to damage it, which so far has prevented large scale attacks on the network.
Is the popularity of bitcoin responsible for the crash in gold prices recently, as libertarians look to invest in something they see as not manipulated?
I don't see how. Bitcoin is still too small to have seen any capital flight from gold solely because of it. Did it
contribute? Maybe, but there's no point in me just speculating that.
Could bitcoin actually be a FED decoy so they can buy all the gold up cheap whilst you are all messing around with something that doesn't exist?
It exists in the same physical world that gold exists. I can't help you if you think you're in the matrix or something, though.