RE: How to plan for your death with code
It's difficult, I thought about the issue myself and came up with no final solution but some ideas similar to yours.
Maybe add key-splitting and also splitting up the encrypted containers. Distribute them to trusted parties that do not know who has the other parts until instructed by the automated email. With this additional layer you might introduce a failsafe for accidental information release that gives you time to invalidate a container.
For example give trusted friends 3 of 5 parts of an encrypted container. Put the other parts 4 and 5 one on IPFS and the other onto another decentralized cloud storage like SIA. Put the passphrase into the release mail and also the information who has which part WITHOUT the bucket/file names of the cloud files. A reasonable time after this email gets sent a second email gets sents containing locations of the last two parts. If something goes wrong, you could in between pull/destroy the cloud-hosted files, invalidating the container.
Also separating both dead-man-switch services on different servers might add security.
if you ever manage to work out a solution that is still secure (even against capture/torture in a "no amount of violence can solve a math problem" way) when the procedure is public, you are king. Please post it then :D
The issue with the "not even capture/torture" is that even you can't be trusted with it, so you 'd need several people having bits of the key. Which means that whenever you want to access your funds you need to ask that other guy (multisign basically). Which is very much not usable.
The idea of a double email is great ! This way if the server fails, you can notice it right away and prevent the second mail from going off.