Do turrets and robots killing enemies count for the Pacifist achievement?

Solution 1:

Yes it does count as killing people, according to the sources I have read because you created the death indirectly by your own hand.

The related note you mentioned: If the man you walk up to laying on the ground has a Zzz its a knock-out icon. If he has a skull its a death icon. The environment will always tell you these things. If the roof is such a far drop that you cannot ID him, assume you killed him.

Solution 2:

On the 'Rotten Business' sidequest, there's a second option you can take that doesn't involve you killing Chan.

When talking to Mei about Chan, select the option 'Other Way' or something like that. Jensen will say something along the lines of, "Is there any other way to get rid of Chan that doesn't involve murder?" Mei will give you a package of drugs to plant in Chan's apartment.

All you have to do is go to Chan's apartment, knock him out using a Takedown and interact with his coffee table. Once you plant the drugs, go back to Mei for your reward.