Snipped by me. Re: assuming other people made mistakes. The attorneys shouldn't, since it's their job to speak for their clients (as you've noted). I also wonder what Sokolova would gain from saying what she did (nothing I can think of), given the circumstances.
IMO, contradictions could matter a lot, especially when it comes to providing each other with "alibis" of sorts, i.e., CR was passed out, MB was putting him to bed, JR was getting ready for bedwhile LS allegedly wanted to party.
One other possible thing: It's been asked why/if JR would cover for CR/MB. But is it possible it's the other way around? Referring to another part of your post ... yes, it appears to me that they didn't have their stories straight and thus possibly manipulated them in one way or another to be more cohesive.
The one thing that couldn't be manipulated, though, would be the phone calls from MB/CR's to JR's and JR's to DR's and whomever's (???). Those would have to be accounted for. If LS left like MB allegedly told the neighbor, would he have still called JR's (to make her his problem)?
I definitely think JR is covering for CR/MB and quite reluctantly. But because of these factors he had to get involved:
1) LS was at his place that night and it was undeniable, too many people knew it.
2) Drugs were involved, but we don't really know all of the angles on this, but it leads to several scenarios.
3) MB called JR at 3:30am creating an electronic trail that had to be explained (but has been totally downplayed!)
4) JR had a history with LS and old family connection. This also could not be avoided and so since he would become a POI no matter what, he could work it.
Look at how various scenarios might play out for JR if he say told the truth:
1) LS dies at CR/MB's at 3:25 MB calls JR at 3:30 panicky.
JR is on the hook and so if they call 911, the stuff about JR's connection and drugs comes out. They test LS and blame JR. JR takes the blame.
2) LS goes into convulsions or seizure at 3:25 MB calls JR panicky
JR comes over, she passes out. They try CPR, she dies. Again JR is on the hook for the same reasons.
3) MB puts CR to bed, comes back LS is gone. MB calls JR. They look outside and she is dead. JR gain is on the hook.
4) MB puts CR to bed, calls JR at 3:30, brings LS to JR's LS then vomits, goes into shock and dies. JR tells him to go home. JR again is on the hook for the same reason.
5) LS is at CR/MB's and something isn't going well. MB calls JR. JR comes over and takes her to his place. She dies, JR on the hook again.
So the way I see it, unless JR knew that CR and/or MB raped and killed her he would have to cover for them in order to cover for himself.
Now, just like MB was telling JR's story to the CVS guy, JR could be telling CR or MB's story about LS's injuries and condition. As pointed out... they did talk to each other. And possibly all of JR's story IS MB's story... he took it for his own to deflect attention from MB. Because if MB tells the truth, then it's JR that would go down. And that may be true for CR too...
The only way CR and MB go down is if they did something to LS, but if it were an accident, OD, from her injuries because she was FU'd, etc... in all of those cases JR could be held responsible. So CR/MB don't say anything about the drugs etc... or directly about JR. Instead MB's lawyer hints at it. In Return JR makes it seem like LS was at his place and he was the last to see her, to take the heat off of CR/MB. very cozy.
What would not make sense is if LS walked out of CR/MB's and just took off down the street never to be seen again and yet JR takes the hit for that. If JR never saw her and she disappeared; It would not make sense that he would take on a story that she was at his place until she could walk. Because then he would know there would be a real culprit and would have no need.
So this narrows it down for me. i can't see JR covering for others raping and murdering LS unless he was directly involved, and whether or not it involved drugs. I can't see JR covering for others if LS walked down the street after leaving CR/MB's and he never actually saw her after Kilroys. Then he might be motivated to find a culprit too. But I can see JR covering for CR/MB if LS died in his presence regardless of location. Also can see JR covering for CR/MB if LS was already dead at CR/MB's or somewhere between the alley and 5N, if he was conned by CR/MB to accept that it was linked to drugs at JR's or something like that. Finally there is the possibility that JR was simply blackmailed into covering for CR/MB. They may have simply said they will tell LE about dealing, etc... unless he covers for them. (a risky thing to do, but possible)