1)
I think Nel accepts what the state was able to prove, but like me I think he believes there is even more that can not be proved. He would however accept a large section of Oscar's version, as it would already indicate murder. The purposeful aiming at the door, with another person behind the door, while he was in no immediate danger. While using four well directed shots, with ammunition which is likely to cause serious injuries or death.
2)
No. But this is a personal opinion. It seemed as though he started giving up hope after Dixon. Van Schalkwyk (whose testimony should be inadmissible) was an act of desperation. He seems to be resigned to the fact that he is merely there for damage limitation.
3)
I do not think the scene was substantially compromised. I do however know (I think it was) Motha messed up by handling the pistol. Not that it mattered, because the accused admitted that he used it. As with many high profile cases, however, they did mess up by allowing too many people onto the scene. The control was not what it should have been, but I don't think it had any real influence or will have any real influence later on.