The only tiding of doom im missing is the absolute last one, after orlando gets shot in the mansion.
If you're missing that one, you likely haven't made it through to the end of the current content.
Any hints or advice on how to get that last one?
If you've made it to the end of Day 10, you'll have seen it. If it's the very last one in the gallery, you can't miss it, even when using the vault.