This must be an awesome post for a change! Thats fascinating! I just checked one of the addresses and there is around 26 grand in that one address so they must have quite a lot by now. I wonder though what mixer would ever accept that much money and it would sure take a long time for the money to be laundered. Of course you also would have to do it with multiple launderers so I dont know what their plan is.
Obviously, they don't need to launder all that amount at once
Moreover, even if some mixer could process that many bitcoins (which is not that many really, to tell the truth), it simply doesn't make sense to dump all these coins all at once unless the hackers are 100% certain that they won't be soon parted with their "hard-earned" and "well-deserved" bitcoins. If they are not so sure (which might well be the case), it would make sense to divide the spoil into small portions and launder them separately and cautiously. Other than that, they might not be interested in cashing out altogether
For example buying $50 Monero for BTC in one round and selling them later for bitcoins. Repeat every week and discharge on exchange slowly. 100% guarantee of anonymity, but it works only if you have bitcoin business.