I prefer (2). If the method is too complicated, I propose a simplified version - option (3)

Use AES Crypt instead of Truecrypt. It is much easier to use.
If you're not comfortable using deathswitch.com, we could just encrypt the text file containing passphrase and ask someone we trust to keep it and to email it to the recipients - much the same way we'd need someone to physically take the envelope out of the safe deposit box & post it.
Once the text file containing the passphrase has been encrypted, we immediately send decryption key to all other treasurers by ordinary email (no need to use bitmessage). This way we can confirm that the backup process has been completed.

What do you guys think? Once we've agreed on the method, we can post it in the main thread.

I would go with option no. 3.

neer.g