This is a committal hearing, not a trial. It's to call evidence to decide whether there is sufficient to send anyone for trial. If the attack alleged is just the one incident, the charges don't make sense at first. We don't bother with such hearings in England and Wales. As I recall, it was open to the court to send someone for trial for any offence disclosed by the evidence, whether or not the accused was charged with it for the hearing, but that must have been a rare occurrence and surely unknown if the offence suddenly disclosed was murder.
The court is being asked whether the death was caused by the assault. If was not, did the accused intend to kill him, even though their actions were not the actual cause of the death? If so, attempted murder. If it was, but they neither intended to kill nor to cause him grievous bodily harm, were there actions so grossly reckless that they caused the death? If so, manslaughter.
If they caused the death, they should be charged with murder, on the face of it. For the full offence of murder, all that is required is an intent to cause grievous bodily harm, not an intent to kill. It is hard to see how they did not intend grievous bodily harm ,but the prosecution must have decided that even that intent was not sufficiently shown by the evidence