I agree with you, though I would reduce the dope probability to "unlikely" down from "extremely unlikely".
Though the area is not needed for a lower level drug sale, it would make an attractive meeting place. This raises the possibility that one of the victims had intended to meet some one there to make an apology, make a promise, provide information, regarding low level drugs, or even agree to "hold" a small amount of drugs for another party.
While a meeting would normally leave a digital trail, I think some criminals, like Al Queda, have learned the hard way about LE electronic tracking abilities and have gone back to olde fashioned word of mouth messaging.
In the end, I think a random perpetrator is more likely, but the arranged meeting possibility though less likely, is still plausible. What bothers me is that a meeting could imply a group. And of course, criminals don't tell anybody about their activities- except their new girl friend, and the "cool" guy at the bar. Yet, there still has not been an arrest.