One was about juvenile records access. I had posted some info about ths earlier which I will reproduce below. But the gist of it, from the statute, is that a juvenile arrested or convicted (in juvenile ct terms, "adjudicated delinquent") of a class A felony, first or second degree murder or capital murder will pretty much automatically have their juvenile record made public. In all other cases, a court order is required. The standard for access is a "legitimate interest". I have not looked at case law to see how that standard plays out in practice.
The other question was about whether death "opens" the records otherwise sealed. In general, no, unless there is something in MO that specifically provides for that, which I haven't seen and which I doubt exists. This type of record access is purely in the hands of the state. If they wanted sealed records available after the subject's death it would be so stated. Also, in general, privacy type rights (which are similar) survive the death of the person. Rights may also reside with the immediate family to protect the rights of the decedent. So, I highly doubt that death, in and of itself, would make the records available. It may be that the circumstances of the death would create a legitimate interest in someone so that they could then obtain the records under the court order standard. And, if the underlying offenses were sufficiently serious, the records would already be available.
