@Ceciliabr

Is it automatically detecting the number of threads available?

Yes, the number of threads by default is the number of available processors (CPU) that will be the maximum value because I noticed a bug by opening your file on my computer which has only 4 cores.

Quite oddly, it seems that choosing different bucket orders has an impact on the rendering time.

I think it depends on the scene.
With yours where the subject is central and the background black, the order has an influence especially on the calculation of the remaining time.

I didn't try the reverse options – but I must admit I was somewhat curious about the reverse random...

The "reverse random" bucket order will be removed.

I noticed no difference with the threads.lowPriority activated.

This is what I also found but I do not do any action in the plan or the 3D view during a rendering.

It seems the video will not render in Q4, but stops about half way.

Version 1.7 of the plug-in uses only the default values of the new options.
I will test with different video format because the lighting significantly increases the duration of the rendering.

Enko