1) Would it be necessary for all MN's in the mixing rounds to be bad actors? Maybe just the "entry" and "exit" MN? Plus one in the middle?
Yes you need to control all the MN's taking part in the mixing.
2) Three-letter organizations don't necessarily have to pay for DRK (hacks, seizures etc)
True dat, and some people have been saying all along that we'd need to move nodes from Amazon et al. to independent operators. Currently people just run them where it's cheapest and easiest and where the step-by-step guides tell them to. When/if the price rises enough so the costs of running a node ($5 a month or $50 a month) doesn't matter anymore people will move I hope. And, if the price really goes skyhigh we'll be running our masternodes on our own datacenters.
3) Even if there was only a 1% chance of your anon transaction getting de-anonymized by bad actors would you really take that chance? And if it were a 3% chance?
Depends on the transaction. You could mix them again to make a relatively high 3% chance to go to 0.09%. And then once more to make it 0.0027%. And even then the party having the luck of "deanonymizing" that transaction, wouldn't likely have enough information to find out who I really am. All they would now have is a collection of inputs that I got from somewhere and that were sent to somewhere.
And to keep things in perspective, it's unclear if it is at all possible to make NSA resistant anonymity. They could have access to all personal computers/laptops already (and if not now, then in the very near future). They might even be recording all internet traffic right now. But to achieve anonymity that will keep regular police, banks, and criminals from finding out your finances, is very possible.
At this point you do sound more and more like a concern troll.
No, he just sounds like someone who is asking the questions he should be asking.