[godshatter]

Probably wouldn't hurt to add an "I'm being coerced into this" version of the secret passphrase while they're at it.

[chii]

while ostensibly true, the more different types of passphrase/words you have, the less easy it is to remember.

You probably only need just one, for authentication purposes. I doubt grandmother can perform this sort of "spycraft" well if it's more complicated. Better to have something simple and easy, than to forget and panic later.