You can play Arché with your Seaboard in Single-Channel-Mode, but you will not really be able to take advantage of much of the Seaboard's special features.
Mapping the bow
Just as with any other MIDI controller, you have to map a MIDI controller element to the virtual bow of Arché. This will allow you to move the virtual bow and in that way get a sound out of Arché in the first place.
Since the sound generation is taking into account the speed and acceleration of the bow's movement, you will probably want to make sure that you map the bow to a control element that offers some travel and that can be controlled independently from the fingers that are playing the actual pitch. Any of the three touch sliders on the left hand side of a Seaboard RISE qualify for that.
Please be aware that the "Natural" and "Hybrid" playing modes of Arché will retrigger the sound when you move the bow backwards (meaning when decreasing the parameter value of the mapped control element).
With the "Expression" mode of Arché the sound doesn't retrigger in that case, but is sustained. This makes it possible to experiment with mapping the bow to e.g. the "Pressure" dimension of a Seaboard as well.
MPE
When it comes to polyphonic playing, please note that Arché is only mono/duophonic and does not support MPE at the time being. Please refer to this article for details: Is Arché supporting MPE?
Pitch Bending and Glissando
Glissandi are not part of Arché's physical modeling engine. In fact, the pitch bend range is limited to a maximum of -/+ 2 half tones, which will not allow the so-called "Glide" technique of a ROLI Seaboard.