I have read ST's book and I'm in total agreement with what you've said here, including your comment about Burke. And I've interpreted "digital" to mean anything resembling the size and shape of finger. I don't understand how it could be determined her injuries were solely from digital penetration.
Digital would generally mean "finger" although the term "consistent with digital penetration" leaves the door open somewhat. I can't remember exactly how the autopsy was worded.
Injuries sustained can be identified by markers consistent with certain events. Penal penetration leaves different signs than digital although I would think a douche nozzle or any insertion wand for certain medications could mimic digital penetration.
Patsy could have used a speculum to assist for cleansing and medicating. Douching is another option. Who knows? I don't but Steve Thomas does.
I'm going to throw out a thought that is PURE SPECULATION. I've often wondered if Patsy had to restrain JonBenet in order to carry out the punishment or cleansing thus the need to use cord in the staging.