Hi Welsh-Punk,
Generally, drag & drop of MIDI files should work fine with Cubasis 2 and Cubasis 3.
However we are not equipped with the Unison Chord Pack, so can not give it a try.
I will try to get in touch with Unison.audio, to provide them with app promo codes.
Maybe there is a chance they test it out.
Hope that helps.
Best,
Lars