new user trying to set up a processing chain

Hi all, new user of sox here. I'm generally unaccustomed to command
line programs, although I can usually get by. So, pardon me if I'm
asking dumb questions  :).

Sox is really appealing to me especially for batch processing tasks.
Right now, I'm trying to think of the most efficient way to make two
copies of a sound, one being the original, and another being processed
in some way eg. pitch shifting. I would then like to mix these two
copies together and perform further processing on the result eg. add
reverb.

As someone who is generally good at putting pieces together, I can
work out how to do this in a messy way. Basically I would manually
mix/process each file. But I unfortunately struggle with efficiency
sometimes, so it would be quite tedious to do this to multiple files.
So, I'm primarily trying to work out how much I can do with one
instance of sox, and if multiple instances are required, where would
they split?
Thanks for any guidance you can provide!