Ogre, a personal work email account is protected by a unique password. The storage system used to be in the work station with server storage either on or off base and a hierarchical backup system. Whilst I was able to have a document recovered from back up I don't know the process for accessing a closed account. Access would necessarily be at server level with authorisation at a fairly high level.
Regarding personal electronic devices you are talking privacy issues, things that the deceased may not have wanted to be seen by NOK on the one hand to things like banking details that they would not want to be seen by 'cleaners '. Tricky one. A similar conundrum is private off-base persons things. On a different forum I have seen advice to give a trusted friend a key, access, and instructions.