Is it possible to hide the administration of a lethal overdose of cocaine and heroin by coating the exterior surface of a condom or the finger of a rubber glove with this mixture since the colon will absorb anything which is water soluble and bypass the liver to process it -- unlike oral ingestion which goes, first, to the liver before entering the bloodstream? No one would think to look inside the colon in search of drugs when performing an autopsy, yes? Since there were no signs of trauma surrounding the anus in the autopsy report, it's possible that a very small, condom-covered penis or more likely a probing finger clothed in a rubber glove and coated with the lethal drugs could have been an attempt at foreplay? And anal sex may not have been pursued if River immediately felt ill and, thus, prevent any sign of anal trauma?
The offer of anal sex could have been contingent upon a promise to "put a good word in" to Depp to allow a spot on the stage for River to perform. River could, then, have been lured to the Viper Room (rather than return home after dropping off his younger siblings) in the hope of a prearrangement of performing that night only to be snubbed, upon his arrival, by an over-booked stage sufficient to motivate River to try anything to get himself on stage, yes?
I agree with the unpopular belief that he was murdered to silence his outspoken, thought-provoking character.