Indeed, I think that having a shared keychain is very important. I have heard of people planned to do such a thing, but never did before it was too late. Sorting out the digital life off- and online will be a mess without it. Do it today.

We have also been moving stuff out of data silos and are moving back to plain old files where possible. E.g. administrative stuff we share using Bittorrent Sync (because it is peer to peer and encrypted) and we store photos in Dropbox (because they are easier to share with family that way). We considered doing everything with BTSync, but on iOS the interface is too difficult for non tech-savvy family.