No, multiple output is not covered. gored passes on all my projects, even containing complicated redo-stamp/redo-always dependencies the same as apenwarr/redo. Not everything is passed in its testsuite, but I did not dig why. In practice it is complete replacement for my needs with the same behaviour.
I haven't followed redo in years. Has there been a solution to the multiple-output-file problem?
Does your version pass the apenwarr/redo test suite (at least where it makes sense?).