Yes to both questions...
Connected via MIDI, you can use the DTX as a controller to enter data to the MONTAGE Sequencer or you can use the MONTAGE as a MIDI Interface — allowing you to record the DTX MIDI Thru the MONTAGE into a computer DAW, like Cubase.
Connected additionally via two 1/4” audio cables you can record the DTX as audio to the MONTAGE Audio/USB drive record feature or you can use the MONTAGE as an Audio Interface — allowing you to record the DTX Audio through the MONTAGE into a computer DAW, like Cubase.

The DTX can be used as a Clock source and/or a modulation source when plugged into the MONTAGE - The link below is an example of real-time interaction between DTX M12 and MONTAGE:
See this video: https://youtu.be/6xkPlzPrOco?list=PLbPXhs3J3MiBO0BB2eEEoOMhqG22ua1Mh