Choir Reduction vs 4-Part Choir default parameters

Hello Dorico team
Is there a reason why Choir Reduction is in Section Players>Singers and 4-Part Choir is in Ensemble Players>Singers?
Also, Is there a reason why Choir Reduction has a brace and 4-Part Choir has a bracket? (Normally, I would expect both to have a bracket.)
Finally, is there a way to set up Choir Reduction with a bracket? Or do you just have to change it after setup?

A 4-part choir is 4 separate section players, not one. A Choir Reduction is one player. That’s the answer to the first two questions.

You’d have to change Choir Reduction after setup. Bracket and Barline change.

Oh, OK. That makes sense. Thanks, Dan.

…So would you have any idea why my Choir Reduction won’t reduce to a single line when one line is empty?
I just discussed this with Leo
So I did setup a brand new Choir Reduction, but same problem…

Best guess is that there’s something hidden that’s preventing those staves from hiding. Common gremlins are lyric extenders and gradual dynamics. Try deleting and recreating the lyrics and gradual dynamics immediately to the left of where you’d expect the stave to hide.

OK everyone. Well, I think I’ve found the answer. It seems that Choir Reduction does not allow staves to be hidden, ever, even when “Allow individual staves of multi-staff instruments to be hidden” (Layout > Vertical Spacing) is checked.
I discovered this by setting up a blank document with 4-part choir and Choir Reduction. 4-Part Choir staves do as one would expect - the staff hides whenever no notes are input. But Choir Reduction never hides blank staves, even if there are notes only on one staff. At least that’s how it seems to me. Here is the test document to see for yourself. (382 KB)
I imagine this has something to do with Choir Reduction being a Section player “instrument”. Maybe there’s someone at Dorico would like to think a bit more about this. It might be useful if the Choir Reduction to drop to a single line.

Wait a second. Don’t add it as a section player. Add it as a solo player…

OK thanks. I didn’t realize that was an option. I’ll try that.

My guess for the brace rather than bracket is because the reduction is meant for a conductor or (more typically) an accompanist (read: organist/pianist). Keyboard instruments use braces.