In order to save clogging up the issue tracker with a discussion about the way this should move forward, I am opening this discussion here.
The current Issue Tracker thread can be found here: #21130: Reconfigure Aeolus Pipe Organ Synth
The other thread which you may find relevant is here: Aeolus Questions
Currently under debate is whether there should be an Aeolus Theatre Organ provided with MuseScore as well as a cross genre classical organ.
There are broadly two types of pipe organ:-
1. The classical organ which is founded on pipes of diapason tone.
2. The theatre organ founded on pipes of tibia tone.
In real life, there is a degree of overlap between the two types, theatre organ ranks being found in classical organs and vice versa.
For examples of the above for the classical organ think Royal Albert Hall, and for the theatre organ think Blackpool Tower. Both these are of course English organs, and you will find that classical organs in particular are widely varied depending on national school of organ building.