I'm working on building out some inheritance concepts that benefit from a thousand years of legal jurisprudence that can help pass bitcoin from generation to generation without complicated technical structures/platforms that can be legislated away more readily and which otherwise expose your holdings to surveillance. In other words, for a thousand years it was none of the governments business what property exchanged hands so long as you paid your appropriate taxes and, importantly, expressed no interest in illegally avoiding taxation after death.
I love companies like Unchained, etc., but the value of your holdings are subject to government surveillance (and potentially seizure) where as if you can house components of your keys with trusted lawyers, under the appropriate circumstances that lawyer is not subject to subpoena due to the attorney-client privilege so long as the privilege isn't being used in furtherance of a crime.
This is a complicate thing I've been working through for a while now but in sum, if you aren't presently committing a crime and do not intend to facilitate a crime, then your holdings are none of the governments business and so you should be able to secure your secrets in a distributed fashion perhaps with a lawyer such that they are not surveillable and subject to pre-crime authoritarian nonsense.
work in progress.