I am very sure recovery would really be hard on stolen funds and the thing they can do as of now is to track such movement of those coins but I do believe those coins would sit for a while on what wallet or either be gradually be deposited to other wallet by the use of mixers. Leaving out trails is the main mission of the hacker for sure.
I doubt that these coins will end up getting deposited or mixed since it may result in these coins getting seized once deposit has confirmed. The entities behind it know very well how things work, and will likely end up setting up a brand new service where people will end up getting these tainted coins in the long term. It's basically like how there nowadays are thousands and thousands of people having tainted MtGox coins that we're distributed through BTC-E during their last years. One way or another, these coins will end up being the best thing the con artist behind this inside job have ever experienced. Something that happened successfully once, will likely be reason to give it another go for a second attempt.
This is true. People keep proposing a "coin blacklist" but it's not feasible. There's so many ways now to break the chain of transactions, through mixers or altcoins like monero, that so many innocent, normal people would end up with "tainted" coins and would be told they can't spend them because they're stolen. This would hurt the fungibility of Bitcoin, and it's why it's never happened.
