I'd like to add this comment to the subject of using theater organ
pipes in a band organ.

The theater organ pipes are probably voiced for an individual
environment when they were originally installed, so unless you are
a highly experienced pipe voicer you'll have something that does not
sound balanced properly.

Also, band organ pipes were made to withstand rough handling, which the
theater organ pipes were not [exposed to].

Having hauled my band organs many thousands of miles over the highways
and by-ways of Michigan, Indiana, Ohio, and even into Ontario, Canada,
I'm certain that ordinary pipes from either a theater or classical
organ would have not stood up nearly as well.

The use of metal pipes of other than the brass type which were designed
for band organ use would probably be a disaster under the conditions of
use to which a working band organ would be subjected.

Just my observations and opinions.

Hal Davis