You could use part of the Launchpad or another one for the pistons to change stops on the HW section of the organ. You can buy small LCD displays driven by midi and supported by HW to display stepper information details in the user manual (pg 202) . One supplier of these displays is Midi Boutiquehttps://www.midiboutique.com/MIDI-Decoders/hwlcd-mini.
Iain