It's also possible to transpose the entire keyboard inside Sonic SE under the MIDI TAB.
(This image is from a stand alone instance of full Sonic 3, but the MIDI Tab is identical in the version of Sonic SE that currently ships with Dorico)
Notice the transpose values, and the fact you can filter zones on the little virtual keyboards.
Say you load a drum kit that comes with Sonic SE, and want a kit piece remapped to play via different MIDI note for Dorico's sake.
Simply transpose everything for the Instrument Slot holding your drum kit with the MIDI Tab in Sonic until that kit piece falls under the particular key that you need.
Here's a thread that's a bit related, as it deals with using the MIDI Tab in Sonic to kuldge together custom kit mappings in HALion Sonic. Just browse past all the CuBase specific stuff, towards the end it shows Dorico/Sonic SE relevant info on how to remap some things in Sonic.viewtopic.php?f=262&t=114798#p629343