Looks like this was sussed out with a few revolutions through the collective. Just to add a little extra commentary...
The note in Appendix 7 are the guidance which precludes the assignment of "unpublished" (for lack of better description) DME arcs during an Instrument Rating practical test. However, the expectation is that the applicant is knowledgeable about DME arcs and can fly them. This is evidenced by the fact that task V.A. "Intercepting and Tracking Navigational Systems and Arcs" remains in the ACS, so instructors need to be sure their students are proficient at this task.
In the particular part of the northeast where I conduct the majority of my checkrides there aren't any suitably convenient DME arcs for use, but when I travel I tend to look for one just to keep things somewhat unpredictable and random. I've used the
DAB ILS 7L a few times over the past few years as Florida is still "home" to my heart.
Unpublished holds are, of course, fair game. Task III.B. makes that clear by referencing "standard, nonstandard, published, and nonpublished holding patterns." The ACS is your friend!
I randomize my holding instructions on every checkride so no two are the same. I've given unpublished holds, holds with DME legs, holds at an IAF on an ILS, holds on the missed approach, holds at GPS waypoints, holds directly over ground-based navaids. It's all fair game and frankly it's pretty realistic -- be prepared for any combination.