That was my general experience with Ghost Mode and Sniper Assassin co-op. So many runs where they clearly weren’t even trying to get Silent Assassin. 
Then by some stroke of luck, I managed to come across @tryagainlater through random matchmaking in Sniper Assassin and life became much easier. And they’ve sat in my friends list on PSN ever since. So tryagainlater, expect to hear from me once co-op is live. 