IMO Trayvon was murdered. But I don't get the same reading from the acquittal that you do. Nobody disputes that Zimmerman killed Trayvon. But murder is a crime, and the jury decided that Zimmerman did not commit murder. Therefore Trayvon is a victim of homicide, but not a victim of murder. Legally, I mean, which is what the jury is deciding.

The unsolved murders list is probably the same deal, it is colloquial and not legal, and with nobody accused and put to trial, it may yet end up legally murder.

I feel like you are really picking apart hairs here.

There is not a huge difference between "the victim was not found to have been murdered." and "the jury did not find the evidence persuasive enough to decide guilt for the charged person for the charged crime". If you want to get really nitpicky, just because "the victim was not found to have been murdered", doesn't mean that they weren't murdered. Whether they were found to be murdered is a different statement than if they were actually murdered.