Number of checkins per day says something about whether the developers are committing often enough. Depth of inheritance says some about complexiity, just like class coupling and cyclomatic complexity. Unit tests per class don't say anything about quality, though no unit tests might indicate a maintenance problem. Cycle time per product backlog item says something about the scrum process.

Specific roles don't exist in scrum, developers are creating the value.

Refactoring is only about the own code, so not about changing an external interface or api.

Automated builds are making builds of the code after every change to the codebase. As soon as something breaks, the developers get informed. In order to automate it, the build process needs to be cleary defined. They're a corner stone for CI.

The timebox for the daily scrum is 15 minutes. The timebox doesn't say anything about a minimum length, just about a maximum length.