1. Your publishing will not override any photos added online, they will still be there.
2. You can't restore these automatically, but you can download them manually, or download a complete album from the Photos and Videos page. FTB version 6 is planned to include a two way synch mechanism, but this will take some time to develop.
3. Check your email box for email from firstname.lastname@example.org. This address might be marked as spam from your email provider.