I think it's too early to talk about data security. We have not even decided what data to collect.
In addition, the idea of backing up an individuals and resurrecting them in a future requires the widest possible publicity.
I don't want to impose my opinion in any way, but we should start with a clear statement - why it is important to collect and back up personal data.
For this reason, we need to find someone who could write this in good English.
After that, it should be clarified what data should be collected. Only then will there be time to think about how to store different types of information.