From what I can tell, benzos (usually Xanax) was a drug commonly used by that group. Mixed with alcohol, it can lead to memory loss (like what CR suffered perhaps) and "severe" intoxication but it does not normally lead to fatal OD's when combined with alcohol as other depressants do (particularly opiates). Cocaine also is not known for serious adverse reactions with alcohol. It is true however, that "atypical" reactions can occur, particularly in people with other medical conditions (like heart trouble).
Among former junkies I have know there are many stories of dealing with the problem of someone OD'ing in your home. Usually, bodies are put in dumpsters or places where they would be found and only far enough from the place where they died so that LE wouldn't make the connection. There really isn't any reason to transport the body a long distance or conceal the body; in fact it would be counterproductive; you wouldn't want a "routine" OD to turn into missing person/murder investigation. Still, this crowd was hardly made up of hardened criminal who would figure that all out.
Capt Q seemed to "play down" the whole story of the "Dark skinned stranger" but the explanation that the "time of the sighting was off" doesn't sound right. This is a woman who just got off work. She would know what time it was. Unless there is some compelling reason to dismiss that report, (and I would expect it to be disclosed) I bet BPD is still checking out the lead. Incidentally, there is a person in B'town who might resemble that "Dark skinned stranger" who has close ties to one of the "second tier POI's.
The above "thoughts" don't rule out the OD theory but they do add a little weight to the "stranger abduction" theory. I keep coming back to the possibility that JR and perhaps others lied about the TIME and Condition of LS when she did leave his townhouse but not the fact that she did leave on her own. They may have not wanted to admit that they let an extremely inebriated girl walk home alone and possibly to her death.
