All the way down the rabbit hole, but no idea how to use it to give it a thorough workout.

kinit is required for it to be able to search/import files (I found that out at least). It has a nice startup wizard, so it suggested that the required parts of mlt for kdenlive are built into it. There were some optional run deps for dvd authoring that can be added also.

kdenlive:

There's potential for shortening the dependency lists, but would need to force the -devel KF5 libs to depend on their -devel dependencies