Ok, after spending some time cleaning up the DMF, it turns out that I was partially wrong on the twist test.
The flywheel rotates less than 15mm in either direction, 13mm to be exact, before it meets much greater springy resistance. However, once let go, it doesn't return to that middle neutral position. How big of a deal is this?
Sure don't want to spend another $750
on a new flywheel unless it's really needed.