Yes, that would accurately describe scenarios 4 and 5, when someone is using full disk encryption. Of course, someone who _is_ using full disk encryption would probably argue that they _want_ a different password for encryption than for their login password for security reasons, unlike OS X that only uses a single password.
However, scenario 2 also requires more than one user preference for screen locking, so we aren't just working around startup (encryption) passwords.
I like your proposed design, and it would fix the issue for all scenarios.
Yes, that would accurately describe scenarios 4 and 5, when someone is using full disk encryption. Of course, someone who _is_ using full disk encryption would probably argue that they _want_ a different password for encryption than for their login password for security reasons, unlike OS X that only uses a single password.
However, scenario 2 also requires more than one user preference for screen locking, so we aren't just working around startup (encryption) passwords.
I like your proposed design, and it would fix the issue for all scenarios.