Thanks for all the discussions and potential answers!
After some experimentation, I am finding the following workflow to be the easiest for me. Again, this approach is appropriate when the instrument does not include keyswitches. I like to have all of the notes for a particular instrument in a single track, so that it is easy to adjust note durations, start times, velocities, CC's etc. I assign that track to a single synth (either PLAY or KONTAKT, for example). Into that synth, I load many instrument presets, each with a different articulation, and each with a different MIDI channel.
Then, I assign a MIDI channel to each note in the track. I found two ways to do this; either by selecting individual notes and using the "Edit Tool", or by selecting a group of notes, and entering a channel number in the "Event Inspector". Each channel will correspond to a different articulation preset.