My knowledge of horses is almost entirely theoretical (I rode one once on an activity holiday when I was about eleven, and spent all my time trying to yank its head up from the grass) ;-)
But I have read quite a lot of books where the characters know quite a lot about horses (including tidbits like 'one must not keep carriage-horses standing in the cold outside the door')...

Poor old Buquet. He doesn't have much of a role even in the book, and of course Lloyd Webber's musical was based on de Mattos (I'm pretty sure there weren't any other English translations around at the time he was working on the project), where he is written off as a mere scene-shifter. Ironically enough Buquet's function in the original seems to have been as an example of a sober, reliable witness whose evidence can be taken seriously!
He is definitely a 'chief' in the French text, though -- and actually, even in the musical he is described as 'chief of the flies', i.e. in authority over the men who do the actual hauling up and down of all the painted backdrops and heavy scenery flats. It's just that owing to practical restrictions he is the *only* one of the stage-hands we get to see.
(In the 2004 movie we do see him working and directing other men up above, just before his murder.)

You're right, "horse elevator" does sound a bit 'selador'...!

it certainly seems like shows where the main draw was the spectacle or some impressive technical effect are nothing new.
They go back at least as far as "The Tempest", which Shakespeare wrote to show off the new 'storm at sea' effects and elaborate scene changes for King James ;-)

A ballet of sinful nuns rising from the grave is probably the most unusual phrase I've heard all day
Apparently it was considered gratuitously shocking, and a big audience draw that didn't have much to do with the main plot -- some other things never change, either ;-p