After several attempts at creating a 4 measure “Dark Bass” user arpeggio, I have come to the conclusion that we can’t specify that the arpeggio behave as either an _ES or _XS type arpeggio.

Is this a correct conclusion? 

If not, what’s the magical combination of parameters needed to “Put a Track to Arpeggio” as either an _ES or _XS type arpeggio?

No you are not given access to the advanced Note Transposition Tables required to make your own.

You can make “Fixed Note” - Plays exactly what you played, when triggered
You can make “Original Note” - Plays what you played, but adjusts to chord quality and transposes to key range.
You can make “Normal” - Plays arp according to control notes and octaves of that.

Fixed Note is ideal for drums/percussion because these instruments to not need any adjustment to trigger note data. The kick will always be found at a fixed note on the keyboard.

Original Note is ideal for musical phrases (both chordal and bass lines) that need to adjust to Major, Minor, Dominant, Augmented, Diminished, Half Diminished etc., chord qualities, and it will adjust to where you play on the keyboard ... But you get to set which Key on the Keyboard will trigger the Original notes. Therefore if you want to create a guitar arpeggio that you want to trigger in your left hand, you can set the original note for the phrase in that region of the keyboard (This is much more user friendly than trying to learn to use the advanced Note Transposition Tables). And allows the user access to being able to create their own custom chord intelligent arpeggio phrases.

Even if you wanted to control a bass line with your right hand you could set the original note to accomplish that goal. The “ORG NOTE” setting can be any key you choose, musically correct or not.

In other words, you could record a phrase that is in C, it makes logical sense to assign it play when you touch a C, but even that is optional.

The PUT TRACK TO ARPEGGIO job allows you to use as many as four sequencer tracks as sources for your single Arpeggio Phrase. Remember the four tracks will need to play from a Voice. Each of these source tracks could be used to add a unique rhythm to your final result.

Thank you very much, Bad_Mister.