Well first of all thanks for the reply Jurgen.
However, there are still some things regarding the passphrases that are unclear to us.
You store all the passphrases in YOUR cloud based RDS databases. Doesn’t that make it some kind of centralized? Databases could get deleted, their services (f.e. Amazon) deactivated or even worse hacked. Or in another scenario, you could shut down your services (Inheriti etc.)
I know the passphrases alone can’t really do any harm but without them, the whole merging process would fail. Thats still seems to me like a single point of failure.
One could give the passphrases, for example, to his own lawyer or an executor to avoid all of this.